Maybe for the beginning you could let it as is Keneth - we will test it (you and many other palyers... me for sure ) and we will find out if the already done improvements are good enough or if we still miss something...
I am mostly having problems in fights on hard/impossible, but many other players still consider them "easy" so hard to discuss balance as each player has his/her own view of "how hard it really is"
The question should be - do we want make archdemon "a teamplayer" or "super-hero"? Meaning - do we want him to take the place of green dragon in combats, or make his abilities more buff/debuff like so the other units would benefit...
I would vote for super-hero -> as I always liked "no-brain" strategies, were I would benefit from his teleport / hit and run ability -> replenishing possible shooter damage or armageddon damage by demon portal / sacrifive (if warrior - these would be the only two spells I would be able to use per one battle ... maybe one more speed, or iron skin
)