Since WS now use the main-hand's weapon damage rating, tweaking some kind of exception on that level isn't really needed. The only thing "broken" about using a sword's damage with dagger WS would be Evisceration, but if you're using a high damage sword, you're giving up the TP gain of something like Joyeuse, and RDM currently has no multi-hit daggers. Dagger jobs like THF and DNC have a number of daggers with over 40D in comparison, with abilities to help boost their WS. So, while we may come close at times, it's likely a good THF or DNC would still use it better. When you consider life outside Abyssea, Evisceration will also lose some steam since its potential drops off when your crit rate diminishes. The other jobs can fall back to Dancing Edge or, in the case of high DEF mobs, THFs can use SA/TA Mandalic Stab.
So, you're basically looking at a choice between individual WS power or WS frequency.
And yes, things that lock us from other things is not a help. Ideally, a RDM should've been opening SCs for heavier DDs and using MBs to help with their damage contributions and riding Convert/Refresh so we wouldn't have had to rest and thus lose TP, but the players basically perverted those abilities into a healer's tool. The rest of RDM's flaws building upon that didn't really help the situation.