I think the loss of battle cry value is being overrated. Having played a couple thousand ranked games of control warrior at a decent level, I'm optimistic Varian would work in a slightly tweaked deck.
The match ups where you are most hurt by battle cry loss are the ones you can most afford to hold him in hand until you feel the game state is favorable. AoE used (in which case filling the board is well worth it regardless), opponent low on cards, BGH drawn, etc. If you don't have the time to hold out, then what does it matter if you were going to get Black Knight in 3 turns?
If you've survived until turn 10, several battle cry minions have already lost some of their value. Shieldmaiden is there to get you to the late game, not gain 5 armor vs control. Taskmaster isn't fighting off zoo from the deck on turn 10, and I'm not losing sleep over potential utility ping value.
Pulling something like Boom is perfectly fine, he's just there for pure value and getting 14/14 of stats + 2 more draws is rather good value. You can look at the card list and think up some scenarios where it would be pretty bad, but it's just as easy to call out Belcher-Belcher-Armorsmith vs Zoo or Thaurissan-Spell-Spell vs heavy control, 25/25 of stats vs a deck without clear, etc. Obviously it will be up and down, but card draw and playing from the deck are two rather powerful mechanics.
