Personally, I am not that bothered about the Thargoids. If they just represent a tougher AI enemy that occasionally delivers Oh Sugar moments as in previous games, what will they really add? A procedural, multi-branched mission generator that creates content as varied as the star systems created by Stellar Forge, a pass over exploration or bounty hunting that adds an order of magnitude more depth, more detailed and varied ambient system traffic or the addition of passenger missions or more NPC persistence would be more interesting to me.
Of course, I would not complain if the Thargoids were manifested as an alien faction that we can interact with beyond on the wavelength of a laser weapon (default to hostile, defend some essential resource, eventually begin smuggling then trading it to them), or as a BSG-style enemy-within reboot. Imagine if Denton Patreus started rewarding transports of Small Furry Rodents to his systems, and is then unmasked as a gerbil-gobbling insectoid analogously to the baddies in the 80s series 'V'.
