Rather than going on in this endless circle of one of us saying they're useless and need a buff, and you saying that if anything they should be nerfed more, how about addressing my key points. To convince me of your position, you'll have to convince me that these concepts are somehow flawed:
I said that I was at this point out of the debate, and dropping my opposition to buffing the siege frigate. However, if you're specifically addressing me and asking me to respond....
I won't address your key points directly, because the issue really isn't your key points, as reasonable and decently thought-out as they are. Rather, I will address my own key points.
In summation, the siege frigate in its un-nerfed form is an inherently "unbalanced" unit. Here are just a few reasons why:
POINT 1:
Siege frigates are one of a few special units in the game that have the power to "directly" cause you to lose the game, in that they take you off of your planets. Capital ships, the TEC (and possibly Advent) superweapon, and culture also fall into this caterogy. But the superweapon is a late game tech, and you will need multiple ones to win the game. Culture is a late game phenomenon, and you will need multiple planets with multiple propaganda stations, plus time for it to work. Capital ships will remain too expensive to build willy nilly in the numbers needed to bomb planet after planet into oblivion, certainly at least in the early game. The siege frigate stands alone as the early game superunit with the power to cause so much harey carey that the game will no longer be fun to play for many people, myself included. For the newb, it is utterly uncounterable, and they will just lose. For the non-newbish average player, it is simply a massive pain to deal with.
POINT 2:
Usually there is some balance between a powerful unit, and how difficult it is to use. It takes skill to use things like carriers correctly. Not with the un-nerfed siege frigate. You just spam them and send them to as many of your enemy's planets as you can. The siege frigate stands alone as an incredibly powerful weapon that is simultaneously incredibly easy to use, strategy-wise, tactics-wise, and micro-wise.
POINT 3:
There is usually some balance between how powerful a unit is and where it appears on the tech tree (pre-nerf Returning Armada didn't appear tech 1). Not for the siege frigate.
POINT 4:
There is usually some balance between how powerful a unit is and how expensive it is (i.e. the more powerful, the more expensive). Not with the siege frigate.
POINT 5:
There is usually some balance between how powerful a unit is and how early it appears. Not with the siege frigate.
POINT 6:
There is usually some balance between a tactic or strategy, and how easy it is to stop or counter that tactic or strategy (i.e. easy tactics should be countered easily, and powerful tactics should be hard/expensive to pull off, and hard/expensive to counter). This balance doesn't exist with the siege frigate. The ease at which you can spam them and send them out is not at all matched with any ease to counter them. Countering them is a nightmare.
POINT 7:
If it's not enough that they directly attack your ability to remain in the game, to add insult to injury they are also one of the few units that directly attack your economy in a major way. Sure, other units can take out mines or trade ports in a major attack. But it will be a major attack, more or less, and either way you cut it, losing mines is not nearly the loss that losing planets full of population is.
POINT 8:
As a harassment/raiding unit, they are completely unparalleled and unmatched. Honestly, the only real counter is to do to your opponent what he's doing to you. Then the game degenerates into a race to see "who can siege bomb who to death" the fastest. Your other option is to try to defend (GOOD LUCK!) and be harassed to death putting out fires all over your empire, while your opponent who is piloting the siege frigate laughs at you and gets his jollies, while probably stroking his dick to boot (see one of the posts on this very thread for a great description of the harassment technique - I saw it many times, and so did everyone else).
POINT 9:
Static defenses are useless against siege frigs. To have any hope, you have to ring all planets with as many turrets as possible, and as many hangers as possible. This is cost prohibitive and not an option. Thus, again, the only option is to attack your opponent with siege frigates the same as he's doing to you.
You will say your points were unaddresed in that there can't be harm in buffing one of the stats of the siege frigate (survivability, attack strength, cheapness, etc). My retort is that I don't believe the siege frigate will lend itself very well to a buff that will put you in your sweet spot, yet keep it out of the hell spot. The devs tried this, it seems, and were unsuccessful. There is no sweet spot with this unit, you see. There is simply "neutered" and "hell." If you start upping one of the stats on the siege frigate, it will jump from where it is now, to OP and unbalanced. There is a name for this sort of phenomenon in engineering. It is called "hysteresis."
The bottom line is, in its un-nerfed form, the siege frigate is literally a superweapon. Oh, it seems innocent enough - just like a lone strikecraft. And just like the strikecraft, one isn't going to do anything. But also just like the strikecraft, swarms are devastating. The difference is, with the siege frigate, only a small swarm is needed (with strikecraft, much larger swarms are needed, not to mention that they are justifiably high up in the tech tree, justifiably expensive, take a justifiable level of skill to use correctly, yadda yadda).
The un-nerfed siege frigate is like a little pandora's box, just waiting for you to open it. It is way too much power rolled up into way too volotile and small and easy-to-use and easily available package. Now, if you want it buffed - I won't oppose you. Go ahead and agitate for your buff. Add my name to the petition for a buff. Since I seem to be one of the lone voices that was opposing such a buff, now that I've dropped my opposition, I'd say you have a pretty good chance of getting what you want.