Direct comparisons with real world navel ship “classes” is often mis-leading. Indeed, the distinctions between “classes” in the real world can be rather tenuous.
A Pocket Battleship was a compromise to get around treaty restrictions and was largely intended as a commerce raider. In principle, heavily enough gunned to sink anything that can keep up with it, fast enough to escape anything that could threaten it.
In Eve, you could argue that Attack Battlecruisers fill a similar role.
There are new ship ideas I can think of - but any new ship should be a trade off; good at something but has weaknesses. The proposal for a tougher, higher DPS battleship isn’t wise. They would be flown to the exclusion of all other battleships because of the advantages they give.
So, what would my new ship ideas include (and I apologise for any abuses they may open - there’s not a lot of rigour in my thoughts)
A small fleet support ship for each empire. A destroyer sized hull, less DPS than a destroyer, modest bonus to remote repair, able to fit command bursts with a modest bonus but only if rigged for it. Maybe modest E-war support. Low tank but able to fit an Assault DC - gives you a chance for your fleet to rescue you. Each capability should be out performed by the specialist frigates and fitting should be tight enough you have to think about what support you offer rather than “everything”.
A set of fast gun Battleships - probably implemented as a bonus to prop-mod performance, maybe with a signature bonus reducing the MWD bloom, or a capacitor efficiency bonus. Critically this speed comes as the cost of tank - these are fast but more fragile.
A turret version of the Stealth Bomber - probably with a reduced sensor resolution to increase targeting time and a reduction to rate of fire for the two Large Turrets you can fit. Similar Alpha or DPS to a Torpedo Stealth Bomber, similar fragility. Probably no bomb launcher. The idea is a arrive, volley, retreat type operation requiring great co-ordination.
Niche ships for variety rather than “better” ships. Whatever “better” actually means. As I said, not thought through, but some ideas.
And it’s be nice if they were new hull shapes rather than re-skinned and tweaked versions of T1 shapes. But that’s art rather than gameplay.