The main issue is turrets. Turrets need new mechanics, purpose and some buffs. No point increasing longevity of big ships when they're all bark but no bite, it will still pose no challenge at all both in PvP and PvE. It just makes the battle slightly longer and thus more boring. ED is not a fast paced shooter, thats CQC. ED is more of a tactical space battle but dragging battles even longer makes gameplay more moot.
Frontier need to start thinking outside the box, stop tweaking figures on excel sheets!!! Having turret aiming/range linked to sensor module quality and introducing turret enhancing modules that shields them from chaff to a limited extent and it also improves targetting and tracking proficiency are one of the many directions Frontier can pursuit. Theres also turret rotation and tracking speed which can be more defined according to turret class, small turrets track faster and turn faster than bigger turrets. A Vulture can indefinitely kite turrets size M+ but it will still get some damage from weak size S turrets. Players have a choice and there is balance, if they want a big ship that can retaliate and hurt things then they have to sacrifice their sweet SCB or other modules to equip turret enhancing modules plus get a better quality sensor module to increase turret range, consequently they then have to re-think about power management and mass too. Make these turret modules tied to respective turret class so players need 3 modules to support Class S,M,L turrets for example. Hell, 1 module supporting only 1 turret is another alternative too, punishing but still viable.
C'mon Frontier, think outside the box... Stop touching excel spread sheets!!!