I believe the developers have stated that they intend to make specialist skills more useful in the future. Hopefully, they'll become a more viable option for single class crafters.
The current abilities aren't actually quite as terrible as players make them out to be. I've tested a 1* weaver recipe from 0 quality and it actually works under average RNG without needing any level 50+ cross class skills. The biggest issue is that I ended up using a bunch of delineations, meaning that it's too expensive of an approach for classes like Culinarian or Alchemist.
However, your risk of an NQ is definitely greater than the standard cross class approach because if RNG is below average, you'll run into problems with CP. With that in mind, reclaim is the only level 50 ability you really need, but the fact that it's needed already indicates that it's a considerably less reliable and tougher method of crafting.
A cross class approach is viable with as few as 4 classes at level 50+, so that's definitely the approach anyone should take. The only practical use I see for specialization would be new single class crafters who want a head start on 1* recipes while still leveling other classes.
