To me the problem is that he has both a high chance Multiple Attack and a guaranteed Counter Attack plus a decent chance for Stun and Multiple Unit Strike. On top of that he has the Speed to follow through with all of it.
The obvious fix would be to take the Multi-Attack out of the Counter and to lower the chance of the Counter. I think other options would be to remove one of those four mentioned (but that might upset too many), remove his Leader Ability (though that only addresses the argument and not the actual issue), or to lower his Speed (which is likely to lead to needing a buff).