the difference between drawing 1 card and 2 is huge. it usually means doubling or tripling the cost.
I'd pay I think 5 mana to bounce two creatures and draw two cards and I don't like bounce all that much. I'll admit that there could afford to be better bounce cards, that there can be a return of bounce without going Capsize / Tradewind Rider crazy, but making a cantrip on a rebound card means two draws and that is key.
I see at least half of rebound cards being playable in some form. I could understand calling the mechanic bad if Teferi were back in standard but really I don't think there's going to be a problem with the mechanic being underutilized.
I don't know, there's that white spell that can be 4 life and 2 cards for 3 mana. That's pretty playable, more for the 2 cards than the 4 life but hey it's still life. Then there's that one that makes a creature for every creature you control, that's pretty good use of the mechanic. I think we should wait until we get some time to play with the cards themselves before declaring the mechanic to be misused.
Is rebound the new double strike? I mean, is this going to be the mechanic that people have to keep reminding people doubles the effect of spells and it's not a casual tack-on to a spell? For instance, a two cost 2 power first strike creature is fine, but double strike is a completely different story. So getting 2 cards for 3 mana is great, and bouncing two of your opponent's creatures as a side effect is rediculous. Really, rebound cards just don't need to be cantrips.
The second use on rebound is optional, so a rebound Time Stop would just have to cost the same as Time Stop and play no differently. Such a poor card for that mechanic.
Blue one is almost good enough without rebound, and two instances of card manipulation and two draws for one mana is careless. I'm also not a fan of 4 damage for one mana unless it is limited to creatures or has some significant additional cost or condition that must be met.
But green Mindslaver, really? A green card to hose turn shenanigans would be better of just skipping extra turns, and honestly as of the first turn skip this dude paid itself off. You don't need to make your opponent lose the game for taking an extra turn, and most decks are fully capable of wrecking themselves when slavered.
I'm on board for Improvies. Extorted Bargain seems like card disadvantage if they rip into a dis, since they get their old hand back plus that many cards, but I'm sure someone would get use of it. I don't get the need for Keeper of the Sundial, like at all. Does green need a way to hose extra turn taking, since there aren't any powerful extra turn schemes out there? This seems like unnecessary blue hosing, and hosing blue in the current metagame is like kicking a sick puppy. With AIDS.
I could see a series of creatures each with two of these abilities, like Nightscape Master and that cycle, or something like that. Unless the abilities are really simple, and I mean like three words each, the card is too busy.
If you don't like that, you could have five cheap wizards that each have some activated ability and have give a better version of that ability to Cosi. Say one has "Permanents you control named Cosi, Overseer of Essence gain "U,T: Draw a card." and "U,T: Draw a card then discard a card." In the right deck you could have the same effect without word overhaul. This approach is more experimental but it might give what you want.
This is much improved. The abilities aren't exactly even though, why would you do 3 damage to a creature when you can instead destroy it? 3 damage to a player would be more appropriate, and on level with drawing a card, but at that stage of the game +3/+3 is pretty weak to tap a 5 cost legend. If you even up the abilities I would suggest giving it an uptap effect, say for 3 or 4. That would be like extending the idea of Staff of Domination.
The difficulty in design is rarely in addition but in subtraction. The idea here could easily become five cards. There's also no need to put certain abilities together, for instance gaining flying and countering spells. What if you want to fly over and attack? Your opponent would have to cast a spell before you attack, and if they didn't you couldn't activate. Nobody really wants a legendary omnibus, especially when you have more line of text than Warp World. Simplicity is the key.
Seriously though, I made it clear a week ago that the poll for the next one should go up then. Emkorial clearly isn't paying any attention, so you really should do it.
I'd pay I think 5 mana to bounce two creatures and draw two cards and I don't like bounce all that much. I'll admit that there could afford to be better bounce cards, that there can be a return of bounce without going Capsize / Tradewind Rider crazy, but making a cantrip on a rebound card means two draws and that is key.
Good point, but it would have been funny.
If you don't like that, you could have five cheap wizards that each have some activated ability and have give a better version of that ability to Cosi. Say one has "Permanents you control named Cosi, Overseer of Essence gain "U,T: Draw a card." and "U,T: Draw a card then discard a card." In the right deck you could have the same effect without word overhaul. This approach is more experimental but it might give what you want.