Or more likely, you held up mana for interaction that didn't need to be used. Now you have 3+ mana that is wasted unless you can spend it on an ability, and a +1/+1 counter and progressing and additional 1/20th towards an alternative win is much better than absolutely nothing.
That reminds me of infect. The first nine points are inconsequential to an opponent if you're the only one playing infect, it's just the final point that kills players. Dumping 30 EOT mana into an enchantment and watching it eat removal is a horrible feeling and makes the card a wasted slot if you included 8t as an alternative wincon without any other synergy.
Something to keep in mind is that Doubling Season quadruples your counters. Putting 5 +1/+1 counters on a creature while Doubling Season is out means 20 growth counters for Simic Ascendancy.
So Doubling Season breaks another card? Sounds like more of an argument to ban DS than another random card.
(Legal) Alternate wincon cards, and ways to stop them:
Approach of the Second Sun: Mill/exile cards from the top of the library after the first cast, force the opponent to shuffle after the first cast (rare effect, and only a temporary solution)
Azor's Elocutors: Deal damage to their controller (only a temporary solution), creature removal
Barren Glory: Enchantment removal (though at least the controller will have no resources to stop you)
Battle of Wits: Enchantment removal (though it requires the group to allow something like an unlimited size sideboard to meet the requirement)
Biovisionary: Creature removal (only temporary, short of a board wipe)
Darksteel Reactor: Artifact removal, and "destroy" doesn't work (note also that this is a state-based trigger not an upkeep trigger, so you can't simply wait until the counter-accumulation is complete)
To the OP, what specifically are the ways in which you think it will be too easy to win off this that are significantly different than other ways to win the game?
I wouldn't hold my breath. This at first glance doesn't appear to be any easier than Felidar Soverign, the easiest path to victory being Avenger of Zendikar and a fetch land or two. However, that still takes a couple of turns, or a dominant board state or a game that's been going on for a while. All of which, I don't feel make for a win-the-game scenario that the RC should be policing. If anything, this is just another win more card in Simic's increasingly obnoxious arsenal of +1/+1 counter strategy (I'm looking at you Ezuri).
(That wasn't a serious question, just how often I see or hear about it.)
Misc. EDH Stuff: Commander Cube | Zombies (Horde)
Resources:Commander Rulings FAQ | Commander Deckbuilding Guide
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That reminds me of infect. The first nine points are inconsequential to an opponent if you're the only one playing infect, it's just the final point that kills players. Dumping 30 EOT mana into an enchantment and watching it eat removal is a horrible feeling and makes the card a wasted slot if you included 8t as an alternative wincon without any other synergy.
Misc. EDH Stuff: Commander Cube | Zombies (Horde)
Resources:Commander Rulings FAQ | Commander Deckbuilding Guide
Follow me on Twitter! @cryogen_mtg
Anyone can start a SCD.
Misc. EDH Stuff: Commander Cube | Zombies (Horde)
Resources:Commander Rulings FAQ | Commander Deckbuilding Guide
Follow me on Twitter! @cryogen_mtg
So Doubling Season breaks another card? Sounds like more of an argument to ban DS than another random card.
Misc. EDH Stuff: Commander Cube | Zombies (Horde)
Resources:Commander Rulings FAQ | Commander Deckbuilding Guide
Follow me on Twitter! @cryogen_mtg
Learn from the Past is a much more fun way to deal with LabMan.
Misc. EDH Stuff: Commander Cube | Zombies (Horde)
Resources:Commander Rulings FAQ | Commander Deckbuilding Guide
Follow me on Twitter! @cryogen_mtg
Misc. EDH Stuff: Commander Cube | Zombies (Horde)
Resources:Commander Rulings FAQ | Commander Deckbuilding Guide
Follow me on Twitter! @cryogen_mtg
The mana it costs to cast this is not quite as important as the mana (and other resources) it takes to achieve 20 counters on it.
Misc. EDH Stuff: Commander Cube | Zombies (Horde)
Resources:Commander Rulings FAQ | Commander Deckbuilding Guide
Follow me on Twitter! @cryogen_mtg
I wouldn't hold my breath. This at first glance doesn't appear to be any easier than Felidar Soverign, the easiest path to victory being Avenger of Zendikar and a fetch land or two. However, that still takes a couple of turns, or a dominant board state or a game that's been going on for a while. All of which, I don't feel make for a win-the-game scenario that the RC should be policing. If anything, this is just another win more card in Simic's increasingly obnoxious arsenal of +1/+1 counter strategy (I'm looking at you Ezuri).
Misc. EDH Stuff: Commander Cube | Zombies (Horde)
Resources:Commander Rulings FAQ | Commander Deckbuilding Guide
Follow me on Twitter! @cryogen_mtg