Well, I've maxed all my stats and I'm not sure what to do now. xD So I have a few suggestions:
One would be to exchange max stats for more items of some sort, like a max stat item and then get the stats reset. This way, players would have an incentive to continue training past their first max stat.
The second would be for the increase in ap bonus per level to have a limit, such as 10 or something. With 50 rebirths, a player would get 54 ap per level. If the player trains to 250, then he'll have 13500 ap per rebirth. Therefore, the player could max his or her stats again in about 9 rebirths. Personally, that seems too fast for me.
Also, as much as I love a ton of exp, 8888x exp events seem a bit much. One skelegon got me 2 levels each from 170 on and by killing like, 15 or 20 of them, I'd surpass level 200, thus able to quickly rebirth once again. Perhaps these exp events should be lowered to 1500x or something.
I hope that you take these suggestions into consideration.