On the player side, bombers are called in to deal with forcefields and fortresses, and pretty much nothing else (seriously, does anyone really use these to go after unprotected command stations?). It's extremely easy to knock out any non-mk5 command station with fighters, so there's no use risking bombers.
On the AI side, bombers are good against forcefields that the humans have, and the command station bonus really doesn't mean much except against the human homeworld command station.
I also feel like it's wrong for bombers to not be the go-to for heavily defended targets (mk5 command stations being one such target). So, the only real problem here is human homeworld command stations being too vulnerable to bombers.
There are probably a couple options available without actually changing bombers:
-Make the human home command station either immune to, or take reduced damage (a la deflector drones) from whatever ammo type bombers use (which, incidentally, is different from that of Bomber Starships), and reduce hitpoints on the human home command station (if necessary - though I don't think it really will be since it dies really easily anyway).
-Give the human home command station an "attrition polycrystal" ability (some kind of sonic resonance weapon that breaks down the crystaline structure or some such), so that mk1 and mk2 bombers will only last long enough to bust the forcefields, and past that the AI will need to use other ships. Makes early bomber waves less of a threat, but makes later bomber waves still possibly game-breaking. (this is probably an unworkable idea, just wanted to throw it out there to get discussion/ideas flowing).
Anyway, mostly what I wanted to say is that Command-Grade bonus is such a niche bonus that shifting it around won't make much of a difference, especially since the human home command station is really the only at-risk target.
Also, heavy is not a disproportionately useful bonus since there are very few ships with that armor type. It comes down to something like Hybrids, Flagships (and light starships?), and maybe one or two fleet ships and guardians (beam guardian). Ultra-Heavy is also not a disproportionately useful bonus - again, it's something like fortresses, armor ships, spire fleetships, and golems (and warp guardians). Fortresses are avoidable, and the others are random (warp guardians only show up at higher difficulties). If anything, it's the fortress penalty against polycrystal that makes bombers disproportionately useful, because they're the only thing that will survive against a fortress - how many people will actually say "oh man, I hate fortresses - oh look, Anti-armor ships and Z Chameleons have Ultra-Heavy bonus, I should take one of those"? Nobody, because they don't have polycrystal armor, and there's not really enough other ultra-heavy to really justify those choices in that way.
I think, really, the most disproportionately useful bonus is polycrystal (because it means you don't die), it's just that fighters weren't getting a 10x bonus against polycrystal like the bombers were getting against ultra heavy. That and there are ways around forcefields - use melee/infiltrators/eyebots to clear the units from under a forcefield, and pop the command station and the forcefield disappears. The guard posts, regardless of their armor types (whether heavy, ultra heavy, command grade, structural), still die to a decently sized mob of fighters, so there's really no point to using bombers against those.
In reality, the only things bombers are absolutely needed for are fortresses, forcefields, and the final AI command station (well, golems as well maybe). Against anything else, the solution is usually as simple as "throw fighters at it" - it could be that you NEED bombers to attack guard posts and command stations, and then you'd have to blow a pile of money on bombers before you even take your first planet, rather than just tossing a cap of mk1 fighters at it (mk1 and mk2 if it's a mk3 or mk4 planet). It just seems that bombers are disproportionately important because they need to tackle the major obstacles, the ones that really stick out in your mind. I challenge any of you to play a game without using fighters, and then tell me that fighters aren't, in truth, the disproportionately necessary fleet ship.
