I didn't originally as well but once you get multiply classes up to 50 the repairs will get costly and while I still find the self-repairs a bit cumbersome (especially since that idiotic "update" of the armory where the majority of the gear is now greyed out beyond recognition - what moron thought of that? why can't we keep the original red / green crosses as before??) the savings between 60 - 75 percent on repair costs (if you purchase dark matter from NPC) or even more if you purchase Dark Matter using your spare GC seals made me to change the mind plus "convenience" of being able to repair anytime & anywhere (asuming you carry enough dark matter) is IMO ballancing out the inconvenience of changing the classes to be able to repair. The saving on the cost of repair will add quickly over the time.
That said - I'd still welcome the option to be able to repair without need to change to the respective crafting class - you can still dissallow the repairs in the dungeons to keep it same as now as you can't change classes there.