Are you going to make a version that supports hi-res graphics, 3D, etc...?
Yes, and No.
The default resolution both in the game player and editor is 320x200, which is very small. Running at higher resolution is actually already implemented, but is still an experimental feature, although it should be "ready" pretty soon. You might have seen that a number of non-RPG OHR games already use higher resolutions.
You can also enable a smoothing filter (enabled by using the -s option at the command-line) when playing at 2x or 3x zoom, which makes things look a little nicer. We may eventually support other graphics scaling algorithms such as 2xsai too.
The current color palette is limited to 256 colors. Sprites (heroes, walkabouts, enemies, etc) are limited to 16 colors each.
The 16-color limit will hopefully be raised in the next release in 2017, Dwimmercrafty. The 256 color limit is harder.
3D graphics will not be supported. 3D games are very far outside the scope of what the OHRRPGCE is designed to do.
...Although TwirlySocrates managed to successfully implement a simple 3D system using plotscripting in his BoulderBeast Demo