GameNerdVeggie13: Is in this Game something like the XP Fountain in Might and Magic 3 in which You get XP in exchange for Gold and are there any Options for Infinite Attribute Upgrades or can You raise them only from one time environment Objects? Is there something like in Might and Magic 3 in which You can get all Skills or must You have a Thief/Ninnja in the Party to Lockpick Chests?
Would try a 3 Member Party only then. ^^
There's no Gold->XP fountain. Even if there were, you wouldn't want to use it because training costs get absurdly high at high levels, to the point where you're not going to be able to afford the level ups that you qualify for them. There's plenty of experience in the game; you should have no trouble getting the XP you need to train everybody to level 200. Gold, however, is another manner, and is the reason you won't be able to train your characters that high.
There's no unlimited source of stat boosts. Every stat boost source either:
* Is limited, or
* Will only work if the stat is below a certain number.
There is a place that will teach you almost all the skills in the game, but Thievery is excluded, so you'll still need a Robber or Ninja. Note that Ninjas and Barbarians have more equipment options in this game than they did in MM3.