They really need to look at the Dola again. People say the problem is the ridiculous weapon spread, but I don't think the Dola was designed to be effective at medium to long range in the first place. It's meant to be a close range brawler: slow, tanky, high dps short range weapons.
The problem is, it just isn't tanky. At all. A few more thousand hp than other destroyers is useless if you have no modules to mitigate damage and are so bulky and slow that a blind man will hit you.
They would have to up its natural armor or give it some dreadnought modules (I'm thinking armor amplifier). Which might be a good chance to review the module system in general. Atm the ships merely differ in guns and stats, but every class has the exact same modules, regardless of manufacturer. It would be much more interesting (and might make stuff like T3 viable) if only certain ships had certain modules - and some would be spread around between classes.
For example, a Gravis might share some modules with the Destroyers while the Lorica sacrifices speed and killing power for extra tankiness both in stats and modules.
Imo that would be much more interesting than just having 3 lines per class in which each subsequent tier is simply flat out better than the previous one
T3's are competitive against T4's
They objectively aren't. "Sometimes able to kill them if the stars align" isn't "competitive".
I've also had T3 games where I topped the charts (not in the Dola of course ) but that was equal parts luck and skill. T3 is just objectively worse in every way than its T4 counterpart, so given equal skill and teamplay, it just isn't competitive.