I happen to like killing computer ai, more so than killing other players. The trick is to find those critters who match up well enough without overpowering you. At the moment for me I am kind of stuck between gladiators, brigands and dark rogues on the one hand and ulbernauts on the other. the human types do not present enough of a challenge but pay fairly well while the ulbers are too hard and do not pay well enough. The only reason the humans pay well enough is that they cost next to nothing in healing, still I do not make enough to have any extra after paying for my next levels. Part of the reason I cannot get ahead financially is that I am trying to train too many things, ax, dagger, sword and melee, as well as three types of armor.
I would also like to train crafting skills but they tend to be too sedentary, i.e. stand here and shuffle icons around. Magic is sort of the same but in its case it just isn't effective enough. my highest level in magic is 11 or 12 and killing one of the human types with it takes more mana than I have. Of course being a kran, I probably have more skill than I ought to, but it still is not definitively clear to me whether my theoretical limit is level 8, 80 or 160.
I think all skills cost too much to train but I am certain it is just a symptom of the state of the game. I also think that buying knowledge should be a lump sum affair so that you know exactly how much it is going to cost before you buy and you can only buy if you can afford it.
I hope I haven't wandered too far afield with this post but I think this thread is like sea-grass, the roots are firmly fixed but the end is flowing with the waves.