Love the game, so I'll spitball some ideas that could improve it in easy ways.

Superspuds: Improvement buyout discount increased to 50% while system has 5 or less improvements. Ship buyout discount increased to 50% while system has 25 or more improvements. (The former is for buying a few key improvements in new systems in the mid/lategame, the latter is a more rare utility, to panic-buy ships in the lategame when your core systems are under attack. Both discounts should be multiplicative rather than additive, of course. Strong as this sounds, it's still pretty terrible compared to Jadonyx).

Dark Glitter: Also gives 10% ship cost reduction on systems with full manpower, and increases the rate that ships on this system gain manpower. (Because let's be honest, the current version does next to nothing; 3 weak traits might be leveraged by a specific playstyle somehow at least).

Obliterators: I have a lot of thoughts on this. I like that they exist, but I'd like to see them as more of a wild degeneration of galactic politics than just an assumed endgame play. Prisoner's Dilemma situation, so to speak. Easy version: empire science production reduced by 75% while researching the initial oblit tech if no other empire has it yet. The person who gets the first strike has to seriously work for it, and then everyone can go wild if they so choose. It's a science malus rather than a cost increase because with the latter method, you'd get cases where someone had produced 25% of the required science, someone else finished it, so the other player gets it immediately.

Citadels: Persist for 2 turns after blocking an oblit shot, just to shut down the "fire 2 at the same system at once" strat.

Superspuds are awful. I would like to see any good change on 'em.
Dark Glitter was somehow ok for Vodyani before latest patch, but now when manpower and essence are tied, there is no need for them at all.