It's time to take a look at the Guramba, a C-Store ship, existing in a galaxy of Z-Store ships. Z-Store ships are supposed to have shiny features. As a C-Store ship, somebody thought that the Goomba's shiny feature should come with some drawbacks.
-Siege mode maneuverability is horrendous
-Engine pwr penalty in siege mode
-Javelin must be charged in siege mode
-Transformation locks out everything else, and firing Javelin triggers transformation.
This last one is actually the biggest penalty IMO because if you leave a sliver of hull you can't finish them off.
-Also kind of unintended, you're locked into disruptors if you want to boost the javelin though consoles.
All things considered, firing off that "free" BO+ comes with some pretty serious downsides. Compared to one of its contemporaries the Gal-X gives up only Saucer Separation, which is not a penalty related to actually firing the lance. Sure there's the drawback of the stigma of flying a Gal-X, but that's neither here nor there.
In the current state of Z-Store ships which get shinies without penalties there's no reason for any of the things which are intended to "balance" an extra, occasional, slightly beefy BO.
If we're going to pick and choose, I favor speeding up transformation time and shortening the lockout on every other ability first with a change to siege mode turn rate a close second. I feel like it's fair that if I'm lining up a shot with a sniper rifle and somebody moves I have to pick up my slightly unwieldy rifle and reposition. The transformation feels like I'm breaking it down to parts every time I want to line up a new shot.