The requirements depend on what you plan to do. If you only want to play with samples, then the requirements are very low. If you want to add effects and VST plugins, then the requirements will depend on these plugins.
The mixer
ReWire support
Global VST pool vs VST per instrument in Renoise (easier for multitimbrality)
Multimonitor support
MIDI export
Oldschool formats support
A couple of pattern commands
Cover image(s) in modules
Built-in chat
I don't know the exact feature list of Renoise, so the list is not exhaustive.