I think over extend is the better choice if one is buffing ones own creatures. That way the melee buffs hit twice, its also a second activation with that creature so if you've moved or pushed yourself away it can chase you and hit again. If you pack a cure, a meridias blessing, a healing wand or the like its relatively easy to remove the stun, and then overextend again if one desires. I like it particularly well with buffed bridge trolls.
Conquer is a strange card. Its really expensive to cast, tricky to execute (gotta control the zone and all), and kind of an all in move. Plus its a dead card if they play no conjurations or a few that don't matter much. Still I've seen it work, but I having seen that its countered by a great many things. Tanglevine a troop I there and you probably arent ready with the teleport to get him out. Or a druid tree could just drop a rooted plant there. So it loses effectiveness agaist a creature spawnpoint, and isnt that what youd wanna use it for?
I can see using it ion a battleforge. But even that's 16 mana plus the 3 it likely cost to own the zone (push or port). That's more than 2 rounds of channel. And Moe mana for a creature. Its just... tough to make work correctly.
