Keith, I'm not going to sugarcoat it. It's not the best kind of nerf. The problem is big, but the nerf should not be this blunt, nor with this haste in development cycle. It should've been a laser-guided surgery.
With these low cap amounts, the starships will never see the light of the day and people will probably
A - Go just for the munitions boosters so that they can use a tactic that's also used by the AI. Yep, blobbing
is a tactic, a brute force one at that but as with all tactics that work consistently, it can get overused.
Starships should be better at boosting that munitions boosters because otherwise munitions boosters become the best bonus ship in the game, easily without a fight. They would be as dominant as Space Planes before they were rebalanced just because attack boosting is so powerful.
B - Never use any boosting at all and hurt for it. After all, you can just build 100 more ships instead with similar metal/crystal cost and have similar damage output without requiring to wait that long to build a mkII/III starship.
C - Going as far as not going to install this patch or the consequent patches that include the same blanket blunt nerf. I'm in this sect at the moment as well. FWIW, I'd rather raise my voice against it and help guide it through as a better experience for the players other than just ole me.
So I too add my vote on MaxAstro's idea:
Light Starships -> Flagships -> Boosters Tech I -> Zenith Ships -> Boosters Tech II -> Spire Ships -> Boosters Tech III -> Core Ships -> Boosters Tech IV
It can be between 10% (too low) 25% (perfect, imo) between tiers, and maybe a slider to change it in the host menu. Range can be fiddled with, maybe dependant on the boostee ship's size. Let's say a starship has only X amount of resources allotted to boosting range and bigger size ships use more of it. So you'll get 300 swarm ships boosted by one ship, or 50 non-swarm boosted by one ship. Picking the targets can be defaulted to base attack as you've proposed.
Ship caps, on the other hand, will hurt more players than it'll help. Frankly, with my playstyle (and a few others I've played with), just using 100-150 ships to finish a game isn't feasible at all times. Blobbing is encouraged by the AI itself at all times after difficulty reaches 7.0, doubly so against turtle types, triply so if you alerted a core/home system. The R/P/S system could've eased it a bit, but with all those possible options the AI has and the player lacks, you can't always formulate a deep-raiding infiltrator special strike team, not with the F/B/C triad plus two or possibly three bonus ships. Especially so when you need the buffer health of the mk1/2 ships. Even if you used raid starships to kite every mobile ship around in a system, the turrets alone create a problem (again, doubly so against core/home) and it's just as bad in the microing sense when you need more than three raid starships for it.
Preventing blobbing is not going to be solved just by removing boosts. Yeah, it's part of the problem, but the game and AI mechanics are also in effect here and doing blanket nerfs is a big nono.