3#Again I agree not because it allows cheesy tactics but because it's unrealistic for the invasion tactics not to cause any damage if the invasion fails.
For both realism and design purposes the biggest issue is that the invasion tactics are poorly integrated with technologies from newer versions of the game, particuarly since the addition of planet types. It's reasonable to assume that aquatic worlds would be much more or less vulnerable to tidal disruption, for example. It's also difficult to imagine much success attacking a toxic atmosphere with spore ships. It's not like people living their have their windows open, after all. You could even make an argument that mass drivers ought to require an asteroid field in the system.
If memory serves, there's also a problem in that most of the tactics lower enemy advantage and comparatively few raise yours. The intentional failure cheese might be less attractive if there were more expensive tactics that favored a massive attacker advantage.
Scattering the tactics around the tech tree makes sense from a realism point of view, but doesn't really match the game. Personally I'd consider making the soldiering branch race-specific and giving each race a soldering theme to match the story. Super hivers would likely concentrate on troop modules and mass assaults, so it'd make sense to me if they had fewer choices of tactics but several levels of troop pods. Master spies would probably be drawn to special ops/special forces types of war and develop relatively expensive invasion strategies based around either reducing enemy advantage or converting large amounts of local support, so they'd have reduced advantage/improvements detroyed or better information warfare options to pick from.
I'd also grey out some tactics based on particular situations. No tidal disruption of water worlds, no spore ships/gas attacks of toxic atmosphere, no mass drivers without asteroids present, etc. Combined with race-specific tactics, that would really throw a wrench in the works. The terrans, for example, might be relative pushovers on small worlds and virtually impossible to dislodge from large ones, in keeping with their general taste of large fleets operating in their own influence. (Especially if their soldering tree granted advantage based on influence instead of invasion tactics.)
In the end, the combination would force you to carefully consider your overall strategy. If you have mainly small planets, you probably don't want to start a war with someone sporting the "Ultimate Troop Module." Similarly if an enemy planet is protected from your most powerful invasion tactic do you pass it up, blow it up, or expend large numbers of troops on it?
