As far as bang for your buck goes frankenslotting seems to work well, never had a 50 so can't really say whether your bonuses will compare with a 'luxury' set build but given I can frankenslot 4/5 charecters easily for the cost of one 'pimped' build I would say it probably still compares rather favourably.
For this I blame the devs, what is the point of 120%+ dmg when it will be nefered to 100% anyway and ED is no equise it apparently went live b4 sets did.
Looking ahead, I think the only thing my controller is going to set slot for is recharge (PermaAM and PermaHasten would be nice - how much do I need beyond the standard 90% (+ change) from enhancements after ED and the two abilities themselves? - although I suppose I can normally rest the downtime if I have to) and defences such as the knockback protection in Kinetic Crash.