I personally think the characters need to be a bit smaller, especially in comparison to nature around them, so you should either make things like the trees larger or take down the size of the people, I'd suggest taking down the size of the people because since this is for an MMO you probably have to make alot of armor, etc, also you can then focus your attention on larger than life enemies, this is an mmo, you'll probably be playing with friends, so why not take on giant golems? I recreated your statue, your statue was too uh, soft-looking, to rid of this problem you add in harsher contrast, essentially make it shinier, human head as comparison. I also edited the health bar so it looks a bit more pleasing, instead of the normal solid bar, just throwing that out there though.
From what I've noticed your people aren't very... real looking and they're also suffering from the fact that they're not in the right perspective, you need to think top-down, like you're looking from above, not like you're looking right at the person. You should look up a bit on perspective, also looking up some anatomy wouldn't hurt at all, it will help your people stand out and look more like heroes.
I hope I've helped some, good luck with your project, I would do an edit on the trees but with the current jpg state I'm just too lazy to take the time to clean it and edit it, though, the person I did isn't an edit, I made him from scratch but for the tree I'd probably just do an edit.