Well I'm only a consumer of these mighty mods.(though I have dabbled in making a few minor mods myself)

I'm playing as Gaul with some{soft} iron man rules (no map selling , only bribing rebels, no reloads) on vh/vh , RTR 5.0 and its given a leash of life to the game for me.

IMHO there are many things to saviour in RTR some of which are probably present in other mods(RTR incorporates many peoples best efforts). One I really liked is the reskinned Romans. Another is the reworked building tree , more logical than vanilla.

Play is more challenging in my Gaul scenario and about to be hammered by the Romans so at this early stage (264) things are a bit hairy and fun.

On the maybe negative , so called fantasy and overstrong units have been toned down or eliminated( like dogs and pigs) so if you enjoy a more fantasy type battle then you'd be disappointed. I think there is definitely room for a similar Unrealism Totalwar Mod( hint) which would be similar in scope to RTR but takes this unreal approach. RTR mission is to be Realistic so think on that.

So in summary I'd definitely recommend it if you have played a few games on Vanilla mode and looking for something else.