okay, look, this is the way i see it, the game is set in trader space, so each soverign planet already has a human population with human infrastructure... so, im not sure with advent, but the vasari wouldnt have to bomb a planet, so much as destroy any land based defenses and set up their orbital lock down structures, as they dont need land based infrastructure so much, advent would have to do the same probably but set up any land based C&C centers, TEC would have the least problems, as they can adapt any of the soverign planets' existing structures, and would probably even have a bonus because they would best understand how the soverign tech works
however... that would be largely unbalanced... and very complicated... this is a game, there is no necessary reason to over complicate things, and for balance, the simpler the better.
so, my arguement basically is that rather than making a specialised way for each race to colonise planets, leave it as is, sure its not the most realistic, or the most proctiacal, or the most morally comfortable way to do it... but its a game, and its war.
if it makes you feel any better, think of it like this: "Infrastructure", could mean weapons and ammo factories, land based defense systems, C&C centers and systems etc, it says so in the little blurb about the Vasari, they dont populate planets with their own people, but use the locals as cheap labour and taxable citizens etc. that said, if you'd really like a change to the way planets change hands, maybe TEC nukes could be interchanged with space-to-surface precision missiles to take out precision targets, and radiation-less nukes for the larger C&C centers.
however, i think that sending in ground troops as and unneccesary change. to be honest, im indifferent either way (though i think the TEC heavy fallout upgrade is totally stupid), one argument i can see FOR troops is for planets with upgrades or useful features, that way those thigns can be preserved.
but i have to say, that making a change to a video game because of a weak stomach or being an incredibly morally conscious person, is wasteful. if its for a good reason, that imporves the game, fine, but for the OP's reason, just a waste. im not being personal, but its the same old arguement with swear words, its a word! being upset by an assortment of letters, is silly, YOU are the only one who gives the word power, and YOU are the one letting the word offend you. same with video games, if you think that a game mechanic is morally wrong or offensive, well, to be blunt, build a bridge and get over it. i realise it may not be easy, and that the word you used was it makes you un-easy, but.... its a game, simply a way of facilitating one aspect of play.
so, i could re-iterate my points and make more points, but its late and i cant be bothered... that and ill probably just offend the OP some more. believe me i do not intend to, im simply saying that changing a video game mechanic because of an irrational un-easiness due to killing numbers (which in themselves are in-conclusive as to what you are actually killing/destroying), is stupid and wasteful.
i would like to, however, finish on this note: do you remember the game lemmings? where u get a number of little green men, 5 pixels high, and you have to assign jobs to them so they can direct the civilisation to the safety of the exit door? well, i used to play that when i was 5, and one of the game mechanics was that once you set a lemming to the blocker job, the only way to win the game was to wait till all the other lemmings got the the exit door and then detonate all the remaining blocker lemmings. i would cry and cry and cry and curse the world and the developers for not programming in a better way to finish the game. i do know how you feel, but Sins is alot less personal than lemmings, and the changing a game because mass genocide makes you uneasy, well, not a good enough reason for me, sorry, but it isnt