Ideally I'd like Thargoids to be a serious game and lore changing crisis, though I'd settle for the outcome you mention as that would imply a decent challenge even if limited in area. Ultimately though I suspect they won't actually be difficult, at most an artificial invinciblity that needs a special module to hurt or avoid EMP. Sure FDEV played up the danger factor, but then they backed off that stance from all the complaints at potential losses due to Thargoid attacks. I'm pretty sure the likely scenario is a Thargoid will be beatable by a half built PVE farming turret boat, because anything harder will be complained about.
As it stands NPCs are too easy, Elite NPCs could use the 2.0 AI, and Thargoids will likely follow the pattern and be something easily farmed, like a CZ or RES.
Thargoid Invasion [HIGH]
Get ready for the invasion, coming to a (semi) permanent USS near you. The idea that they are a "game and lore changing crisis" falls apart when you realise there are a bunch of intractable who will not stand for it and will force frontier's hand. We already know this. We had that post 2.1.
They won't roll through the bubble. They won't frighten traders into shields, or give combat aces a sudden desire to change pants mid-jump within the bubble. They will be the same AI we have now, likely with mental high resistances and armour and what not that need "the magic sauce" to defeat. All available, of course, behind engineering grind.
PVP people will take all of about 5 nano-seconds to identify the correct meta to make them, essentially, an irrelevant force in a fight and will promptly go back to shooting commanders.
Normally, invasions mean
they invade; this appears to be a reverse-invasion, where
we (essentially) invade. Understand it's very simple to make AI very hard to kill. It's called "bullet sponge" and is a massively overused methodology. Just make it a wall of resistance and armour that takes hours to pound through. So standard weapons likely have huge debuffs to blunt their effectiveness. The AI doesn't even need to be competent. Just a large sponge.
I really, really hope MoM has been able to gift them some special manners. I really really want that first encounter, if the shooting starts, to be extremely short and quite violent.
Make me run. I should have to run.
Or die, if I am not prepared.
The hilarious thing will be if building for thargoid bear,
also means highly effective against commanders; it's just going to mean PVP people farm the invaders so they can continue to stove commander heads in, in the most optimal fashion possible. I do hope Frontier has worked that
virtually guaranteed scenario ahead of time and has "thought of that" because past history suggests no they won't have at all and it's going to lead to comical amounts of destruction.
We shall see?