The fact that capital ships can only ever fire forwards is, and has always been, ridiculous. We can look at almost any sci-fi we want, there's practically no precedent for this kind of norm. Small ships dart around, dodge impacts and fire forwards. Big ships sit still, tank damage and slug it out in whatever direction it's needed. Certain directions might be more favorable than others, but most of them work just fine. Not to mention broadsides. We see a lot of broadsides in media.
Thus, I support the concept. Big ships need to be able to fire their main weapons, independently of their main body.
I'm not so sure about this implementation. There needs to be balancing, for example, a powerful weapon should always aim slowly, even if it's fired through a small turret.
I would also like, for once, to see this implemented with physical blocks. Every bloody thing in this game is an invisible link. Power transfer, item transfer, logic, shield dispersal, etc. This one thing I'd want to use something tangible. Something like, one output on the mothership, one intake on the turret. In the turret's default orientation, these must touch. When the turret moves, the link remains as long as both blocks are not destroyed. The gun on the mothership must connect physically to the output block, as if it was supposed to fire the shot through it.