Thanks for all the input so far! I'm trying to get as many improvements implemented as possible for the next update.
I think it'll be worth to work on Emps-World oldschool as side project a few days a week. I had a good idea today on how to map all monster ids with the current monsters and it worked out nicely. I think I'll be able to have an oldschool Emps-World clone sooner as expected. I'll try to get one up as soon as possible and see if people actually enjoy playing that way. If we get good feedback and an increasing population, I'll continue the oldschool project and work on more features.
Anyway, here's a progress screenschot:
I will be using the emps engine, because it's faster (better performance), looks better (no screen shaking) and has lots of optional eye candy (shadows, fog, ground, water, etc.).