I don't remember them from the C64 days.
I think I remember them from playing Oolite about 7-8 years ago, but it may be from back in the 90's on the PC (sorry - I cannot brain today - I has the dumb). What I remember most was dying a lot. There was a mother ship and multiple drones that were extremely fast and maneuverable and attacked on sight. You had to be very fast and accurate with your mil-spec laser to have a chance. Eventually I got to the point I could survive an encounter. I think if I shot down the drones, the mother ship would fly away, but maybe I took it out too (or I ran away).
Anyway, back then you had the saved game so dying a bunch of times wasn't a big deal. It might be interesting and exciting to run across some Thargoids in ED, but if FD makes it so they can disable and destroy you like a sitting duck, until you get special weapons and protection, then I won't enjoy that at all. I think it would be better if a decent combat ship could take out the drones, but I'm still worried about that mothership just shutting down all the systems. I hope they will be able to update the galaxy map to show the Thargoid area of operation so it will be easier to avoid them.