I am really happy about the recent kinetic buffs and reworking of mines. Let's keep improvements like this coming please! This makes mines so much more appealing and gives so many possibilities for builds and tactics.
Something I'd observed about ship sets is that at end-game most everyone has the same few sets: the STF Borg, Maco, Omega, Honor Guard.
I would like to suggest that you bring the Jem'hadar, Breen, and Reman sets closer to par with the STF sets. And more importantly give them bigger advantages so that you bring an interesting balance to PVP via a system of checks and balances, that is to say tradeoffs.
This would mean my opponents are not always going to have plasma resistance so I can use plasma weapons sometimes.
Here's a possible scenario: Give the Breen set a strong resistance to phasers. Give the Jem'hadar set a strong resistance to antiproton beams. Or whatever combination makes sense canonically. Improve the Reman plasma torpedo bonus (not just for HY anymore) and add a bonus for plasma beams, too. Give them disruptor resistance.