There is a clear trend in multiplayer towards heavy cruiser spam. I see many people completely bypassing the lower upgrades, teching for heavy cruisers. Whether you do it normally with some civic upgrade or just rush it alone, it is very effective. Too effective.
How? Because the lower military tier upgrades are too unnoticable. I mean 5% faster shield generation or 5% stronger lasers, almost never make a difference. Thats why it is so attractive to just bypass them and go for heavy cruisers, because they give you so much more health and firepower at once. A player who spend research in the lower shield/armor/weapon upgrades is almost always outmatched by a player who techs for heavy cruisers. A similar development, although not seen as often, light carrier spam.
Why is this bad? Gameplay gets repetetive and predictable. Players are forced to cruiser spam to compete.
How to fix it: Nerf Heavy Cruisers? Wrong. They should be quite stronger than frigates, like they are right now. There just have to be alternatives. And that should be the lower military upgrades. The effects should be at least doubled, if not tripled (5% -> 15% etc.)
so that the effects are noticable. This still doesnt make frigates uber ships, but if you research many of these lower upgrades, you are at least able to compete with a heavy cruiser spammer, allowing more gameplay variations.