It's conpletely different. Theres a 30 hour story (which im finding really entertaining so far) Dozens of side quests, dozens of jobs, a lengthy base building sub quest (I'm 20 hours in on that one and its really fun). It has a space fleet managment meta game, there is emergent gameplay all over the shop from new easter eggs type deals as you explore and ontop of that the prodecural generation is overhauled making everything look so much better than 2 years ago, planets are much more beutiful, interesting and really surprising at times, sometimes I don't want to leave them. Even the third person cameras make the game feel different and much more enjoyable for some reason. The drop in, drop out multiplayer is great.... basically everything except for the first two hours is different. There is triple if not quadruple the amount of content and it's good quality content too.
It's well worth returning too and I'm so glad I did.
Well good on them for fixing it.