Umm. Torpedo's are basically big missiles in ACTA - NA, any bigger and it's not as efficient. The previous entry on Q-ships would probably be good for civilian weapon platforms. As far as attacking planets, the church has instigated fleet bombardments many times - it's a preferred method of theirs to weed out pockets of the faithless, heretics, tech users, etc!
Gunboats revisited
Whilst the smallest fleet ships in the game so far are explorers, frigates, etc. I think there would be a role for a gunboat - as a large multi-mission fighter type, similiar to the 'Raptor' from BSG. Less able to dogfight, it would rely on fighter escorts to keep enemy fighters away, a dodge roll of 6+, and be able to carry different weapon packages (a single gatling laser, or more micro-missiles (no one-shot), or a grapple gun and 1 troops, or one of the EW packages discussed in the thread).