Lack of Darkslick Shores isn't as obvious a mistake as it might seem; I haven't had a lot of colour problems with the deck as-is, and on the other hand you often need every land to be untapped the turn you play it - land-heavy draws often come down to flashing back Sever the Bloodline (which, by the way, is a fantastic removal spell - it kills Wurmcoils without giving them tokens, and has flashback to boot) or Forbidden Alchemy.
The land count is low, but so is the curve, and I tried to cram as many instants and sorceries in as possible.
Snappy should have a slot in theory, but in practice I can't see what to cut; each of the creatures serves a key role (Skirge and Delver are 1cc threats and probably the most replaceable, but the Stalker and Skeleton are often an unstoppable threat in conjunction with the Pike).
IMO you want to draw a pike ASAP, so the probe lets you dig on your first couple turns as opposed to think twice. I don't like a counterspell with casting cost of three in an aggro build.
I have been running my own pet deck since Innistrad came out. While it is not really U/B, or really a skies deck, or really a pike-based deck, It is a little of all of those. It has many similar themes as yours and is not your usual Delver deck either, so I thought I would share my build since it may help you and I'm also looking for feedback on it as well, so feel free to share your opinions.
Cards that wreck my day: Gut shot, Arc-trail, Mayor, Lilliana, Chandra, and to some extent Giest and other hexproof because it forces me into an uphill race (can't counter everything forever)
The advantages of my list over yours:
1) You are always screwing your opponent up somehow. It's just fun.
2) Better ways to deal with Wurmcoil if you are worried about that. Vapor Snag + Silent Departure + Psychic Barrier + Snapcaster-> repeat until the game is over.
3) No Chance of color problems.
4) Inkmoth and snapcaster mage provide random surpise wins with pike on them. Especially fun in games you would otherwise have no right to win, but your opponent exposes themselves out of overconfidence. (examples: dump your hand at EOT. cast pike, equip inkmoth, swing for 10+ infect. or EOT snapcaster, flashback vapor snag on blocker. Pike, equip, swing for lethal)
5) usually wins just as easily with/without pike, yours almost NEEDS pike to function at all
6) more countermagic, repeatable with snapcaster
7) snapcaster can flash in to defeat Chandra and Liliana sometimes, similar with inkmoth
8) you have 20 ways to flip delver, I have 28
9) owns just about every mid-range strategy
10) I can use vapor snag to save my own dudes if needed, or if I COULD counter , but need to hang on to that negate/mana leak for later
11) I can win with one land against creature strategies, and I have done so several times. Not ideal of course...but possible
Advantages of your list over mine:
1) You have stalker which evades most removal and if piked probably means game over. Also means you don't scoop to resolved Chandra.
2) Skeleton: similar to stalker.
3) Tribute to hunger, more creatures, and more pike to provide some aid against hexproof strategies
4) think twice and skeleton which is good VS permission and some other control
5) your much higher land count means you can use mulligans more to your advantage, getting better hands or game 2/3 searching for your SB hate if it's needed to win (but this is a double edged sword because you need 2 colors too)
6) arc trail and gut shot will still mess you up a bit, but not nearly as much as they do me.
My suggestion to you:
remove all your black spells, black lands, and think twice.
Drop land count to 18-19 since you no longer need all that mana.
Put in inkmoths, snapcasters, negate, vapor snag, probe and dont be afraid to play snapcaster without flashback just to beat face at the end of their turn if you didn't need to counter, because he can win the game for you without flashing back something.
Other thoughts:
Skeleton is the only good reason to run black at all. Red and blue have all the good stuff for abusing pike unless you are trying to infect. In red I'm thinking especially of spike shot goblin with negate and manaleak to make him stick and up the bonus from pike at the same time. Kurin outlaw and desperate ravings scream "abuse" as well. Reckless waif/stormkirk noble with cheap burn spells to either clear a path for them or go to the dome seem like no-brainer additions if using red as well.
4 Vault Skirge
4 Invisible Stalker
2 Reanimating Skeleton
1 Aether Adept
4 Ponder
2 Think Twice
4 Mana Leak
2 Dissipate
4 Forbidden Alchemy
4 Sever the Bloodline
10 Island
4 Swamp
4 Drowned Catacombs
3 Nephalia Drownyard
4 Tribute to Hunger
3 Steel Sabotage
2 Dissipate
2 Reanimating Skeleton
4 (memory fails me)
Lack of Darkslick Shores isn't as obvious a mistake as it might seem; I haven't had a lot of colour problems with the deck as-is, and on the other hand you often need every land to be untapped the turn you play it - land-heavy draws often come down to flashing back Sever the Bloodline (which, by the way, is a fantastic removal spell - it kills Wurmcoils without giving them tokens, and has flashback to boot) or Forbidden Alchemy.
The land count is low, but so is the curve, and I tried to cram as many instants and sorceries in as possible.
Snappy should have a slot in theory, but in practice I can't see what to cut; each of the creatures serves a key role (Skirge and Delver are 1cc threats and probably the most replaceable, but the Stalker and Skeleton are often an unstoppable threat in conjunction with the Pike).
-2 Think Twice
-2 Dissipate
-2 Sever the Bloodline
+3 Gitaxian Probe
+3 Snapcaster Mage
IMO you want to draw a pike ASAP, so the probe lets you dig on your first couple turns as opposed to think twice. I don't like a counterspell with casting cost of three in an aggro build.
Hope that helps.
14 Island
4 Delver of Secrets/Insectile Aberration
2 Phantasmal Bear
4 Snapcaster Mage
4 Vault Skirge
4 Psychic Barrier
4 Gitaxian Probe
4 Vapor Snag
4 Ponder
4 Negate
4 Mana Leak
4 Silent Departure
2 Runechanter's Pike
Cards that wreck my day: Gut shot, Arc-trail, Mayor, Lilliana, Chandra, and to some extent Giest and other hexproof because it forces me into an uphill race (can't counter everything forever)
The advantages of my list over yours:
1) You are always screwing your opponent up somehow. It's just fun.
2) Better ways to deal with Wurmcoil if you are worried about that. Vapor Snag + Silent Departure + Psychic Barrier + Snapcaster-> repeat until the game is over.
3) No Chance of color problems.
4) Inkmoth and snapcaster mage provide random surpise wins with pike on them. Especially fun in games you would otherwise have no right to win, but your opponent exposes themselves out of overconfidence. (examples: dump your hand at EOT. cast pike, equip inkmoth, swing for 10+ infect. or EOT snapcaster, flashback vapor snag on blocker. Pike, equip, swing for lethal)
5) usually wins just as easily with/without pike, yours almost NEEDS pike to function at all
6) more countermagic, repeatable with snapcaster
7) snapcaster can flash in to defeat Chandra and Liliana sometimes, similar with inkmoth
8) you have 20 ways to flip delver, I have 28
9) owns just about every mid-range strategy
10) I can use vapor snag to save my own dudes if needed, or if I COULD counter , but need to hang on to that negate/mana leak for later
11) I can win with one land against creature strategies, and I have done so several times. Not ideal of course...but possible
Advantages of your list over mine:
1) You have stalker which evades most removal and if piked probably means game over. Also means you don't scoop to resolved Chandra.
2) Skeleton: similar to stalker.
3) Tribute to hunger, more creatures, and more pike to provide some aid against hexproof strategies
4) think twice and skeleton which is good VS permission and some other control
5) your much higher land count means you can use mulligans more to your advantage, getting better hands or game 2/3 searching for your SB hate if it's needed to win (but this is a double edged sword because you need 2 colors too)
6) arc trail and gut shot will still mess you up a bit, but not nearly as much as they do me.
My suggestion to you:
remove all your black spells, black lands, and think twice.
Drop land count to 18-19 since you no longer need all that mana.
Put in inkmoths, snapcasters, negate, vapor snag, probe and dont be afraid to play snapcaster without flashback just to beat face at the end of their turn if you didn't need to counter, because he can win the game for you without flashing back something.
Other thoughts:
Skeleton is the only good reason to run black at all. Red and blue have all the good stuff for abusing pike unless you are trying to infect. In red I'm thinking especially of spike shot goblin with negate and manaleak to make him stick and up the bonus from pike at the same time. Kurin outlaw and desperate ravings scream "abuse" as well. Reckless waif/stormkirk noble with cheap burn spells to either clear a path for them or go to the dome seem like no-brainer additions if using red as well.