While personally I don't like it either (even if the helm they introduced still allows the user to cast cantrips, a step up from the original version), there are so many spellcasting classes nowadays, and many of them have enough abilities that casting is just another ability.I don't want ships reliant on spell casters at all personally. I think it's a silly limitation. I know, I know, I'm veering off the beaten path of precedent, but I don't want the a whole campaign contingent on having a (functional) caster. I don't like the helm preventing casting either, but my core problem is deeper.
What I would do is something like, you expend a slot of X level, and the ship travels either Xmph for 1 hour, or at a standard rate for X hours. Or you can choose to expend Hit Dice instead of slots, letting even non-casters take the helm for a bit.