I'm.. not sure where you're seeing battleship spam, Scumbag... I certainly don't see it. I see a lot of snubs. I see a lot of transports. I see the occasional cruiser. I haven't seen a battleship floating around that wasn't me for....a while now. Granted I do play during US Central evenings, so server population is usually under 100, and I have been avoiding the Rheinland-Liberty-Gallia warzones.
But still, I don't think bringing BS in line with every other class of ship - i.e. good at killing itself plus at least one other class - is just cause for attaching extra death penalties.
Making BS slower? ... I don't see the point... they're already the slowest ships in the game (barge notwithstanding), don't have thrusters and don't have CDs. Anything that wants to get away from a battleship... can. Thrust on, mouse flight, and throw the cursor to the corners of the screen. All this is going to do is make it more of a PITA to get around Sirius. If that's what it takes to get some proper anti-cruiser guns, I would absolutely make that tradeoff, but again, I don't think it will serve any purpose other than to frustrate the person flying it.