I have similar issues with the Spire, though I suspect as more medium guns are implemented we will see more guns suited to the Spire's role as a sniper.
My problem is, the Spire is already a decent sniper, it has 1 light and 1 medium gun facing forward, but it's manuvering lacks options, it can't keep distance because it's deadfully slow and while its turning speed is enough to keep your guns on the enemy while sniping, it's not enough when you want to quickly turn and run away, basically (and I realy hate to say this) if you get mean looks from your enemy you are probably going to blow up shortly after cause there is so much a pilot and his engineer can do to keep the Spire afloat. I just feel it's a bit to fragile for the speed it has.
For starters, at least if it's gonna keep being as fragile, I'd like to see it being more agile to support this weakness, or become a bit more survivable in the form of the hull requiring less strokes with a spanner to be rebuild, so you can tank a bit 'Squid Style'.
I have survived my fare share of difficult encounters with the Spire, but it was probably my enemy not being competent enough, I have abused Hydro, Vent, Tar and Kero to the max in order to achieve this and it's still not enough to keep us afloat sometimes.
Then again, I'm no game designer, so I might not be correct, but I still think the Spire right now is not where it should be.
Matadoring Pyra's all day is a hard job.