How about these ideas?

[artifact]

4 Mega Millstone
X:discard X cards from hand and remove X cards from the top of target players libraryand place them in the graveyard.
(Messed this up when i originally wrote this.)

1UU Repeating Failure
Counter target spell. If Repeating Failure is in your graveyard, you may spend 2UUU during your upkeep and put Repeating Failure in your hand.

WW Soldier of Life
During your upkeep, if you control 4 or more creatures. Gain 1 life for each additional creature past 4.
1/1

Just a few ideas that i have.

 

[Istanbul]

Mega Millstone is a super-Jester's Cap. I'd have to say NO.
Repeating Failure concerns me. Make it UUUUU to regrow it; the idea of a buyback counterspell based on mana makes me squirm.
Soldier of Life seems fair.

 

[artifact]

I fixed what i meant to say with Mega Millstone as for the other 2 cards. You got to remember the key to playing counter spells is to have mana. You would have to have 8 mana to buyback and cast it in the same turn. As for Soldier of Life, I thought that would be a good card for a white weenie deck.

 

[Dead]

As much as i'm a fan of milling, mega millstone needs a few changes. Either make the discard from hand a cost rather than effect so you can't mill them for 10 when you only have 1 card to chuck; or make it a sacrifice so you just get one shot out of it. Otherwise it's too unsymmetrical compared to whetstone.

Repeating failure is i take it a hammer equivalent. I think it's fair because counterspells can't actually kill players whereas hammer can and it's quite pricey to recur. However, wizards indicated that they didn't like the idea of mana-recurseable counterspells when they made forbid a discard to buyback- maybe make it UUU and discard a card to return it.

Soldier of Life i think is great, a powerful effect but on a vulnerable card, it only gets rolling later in the game but is too valueable to risk in combat before then, and they should be able to find an answer to it, plus few people could resist overextending to boost it's effect and then regret it when the board is swept. The only problem is with big saproling swarms but if you've got that many of the things you'll be winning soon with or without this card. Definitely my favourite of the three.