I'd be surprised if we don't get "ultimate" or at least "decent" WSs on the way to 99.
If they beat empyrean WSs, then Empyreans start losing out pretty heavily. Even relics would begin to deteriorate a bit (the ones that have useful aftermath/Ws properties like Amano/Yoichi/etc).
Empyreans will still be easy to get weapons that offer strong performance over AH/NM dropped alternatives.
Any person that plays a job often should acquire an empyrean for that job. If they're serious and have the funds, they should work towards a relic/mythic for that job.
As the game stands now, if you don't have an empyrean for a specific DD job, then I'm not sure why you're coming that job to an event.