well, H&R idea IS to over-powered, I'll even (and am now again) admitting that. imagine sending in 1 tril yellow jackets on the H&R mission, knowing not a one will get destroyed, but possibly wiping out the entire enemy armada. probably create havoc on missions and encounters as well.
but the SG idea is not actually as powerful as you say, it is a 2-edged sword of sorts, it gives you more then 1 round to 'finish off the enemy' but it also gives them the chance to do the same.
hp boat does 0 damage to swarmers
swarmers does 1/4 total damage to hp boat
normally, it would end there, but if it continued, the hp boat would lose horribly, this would also put more emphasis on defense (as far as I can tell, defense would have to work 5+ times to be as effective as just going with hp, this giving it it's chance to subtract damage 5+ times)
also... you might have more of a point on the gun turret thing then you may think... looks like I will be putting up another suggestion, lol. (though probably to super-complicated to actually be put in, but meh, probably not as much as that galaxy project and council
)