MArcomage

This card is bad for an uncommon. Compare it to War elephant: Devestator costs more yet does less damage for the condition. War elephant only needs 2 other keywords to make the enemy wall 0 while Devestator needs multiple other barbarians to achieve the same effect. I suggest upping his base damage to at least 50.

And maybe limit elephant's power: total wall reduction is too much

Yeah, I don't think that this card is too weak as it is. The problem may very well be that the elephant is too strong -- I use it in my Hidden Games deck because it can end matches very unexpectedly. Devastator can only be used effectively in its own specifically favorable scenario, but in that situation, it's a fun little nightmare defending against it.

Just to play Devil's Advocate though, Beast/Soldier doesn't really have good synergy (with only two cards sharing the keyword, and those same two cards being the only ones that benefit from the synergy), so to get the right combination of keywords to play Elephant, either:
a) You're using an otherwise unoptimal deck combination (i.e. one with a somewhat balanced number of beast and soldier cards)
b) You're using a primarily Soldier or primarily Beast deck, and relying on sheer luck to happen to draw the other keyword.

On the other hand, if you're playing a Barbarian deck, then it's only natural that you'll have lots of Barbarian cards on hand, and it helps you in other areas.

Or War elephant is good enough to build your deck around using it (and Imperial griffin) since you can play it early and reduce the enemy's wall to 0.