..which still does nothing with regard to allowing Mil SBs to project any power or prevent them from being completely ignored by the attacker.
No, since the projection point was already covered by the buffed attendant fleet. Ignoring them is fair enough, if the enemy doesn't mind an area where your ships are made more powerful and his ships are made weaker. He can, of course, also completely ignore your fleets, if he doesn't mind areas of space where you can attack him with impunity.
Look, I'm not saying that mil bases couldn't use a buff - the effect of their support is pretty limited, and I personally play with all the rings unlocked so they don't preclude each other. But there's no need to completely rework them, as you seem to be lobbying for. They're equivalent to Civ 4 forts. You have a stationary building which acts as a force multiplier around it. That's not a problem imo. They don't need to act as a fleet replacement, since that's not their purpose - they're an augmentation to a fleet.
The arguments in favour of changing them are all basically a matter of using them incorrectly. Those who argue that they're not strong enough to defend themselves aren't garrisoning them. Those who argue that they can be ignored aren't using the debuff modules (they can wipe 30% off enemy movement, and add 70% to the cost of moving - that more or less halves enemy movement overall, which will halt most fleets traversing their ZoC prior to endgame). Those arguing that they can't project power aren't using them to buff an attendant fleet (usually in combination with not garrisoning them).
I'd like to see the 'level' of starbase defences match up to a tech-equivalent max-size ship, which they currently don't at all (so attacking it, the defender gets a 'free' big ship). Currently, they fall behind before Huge. And I'd like to see an additional level of buff/debuff modules balanced for endgame, so that (for example) end-game engines don't laugh at the slowdown effect. And yesw, I'd like to see a hitpoint increase just from adding any module, since destroying a starbase with 30 modules should be harder than killing a naked one. But I just don't see any real reason to rework the basic mechanic of a ZoC-wide buff and a large garrison; that's works fine imo.