I think that the Renown system is ''work in progress''
After all this is a totally new system and only now as the first few guilds reach the 100 mark can anyone look back and study the effects.
I think it is safe to say that the bigger more family orientated guilds are the ones the system seems to be disadvantaging the most.
The big guilds all got off to a flyer but they seem to be bottoming out in the mid seventies. The guilds where DDO family is more important than hard core raiding and renown.
So from my perspective a tweak is required but not major surgery