The combat is some of the best I've ever played. Encounter design is mediocre at worst, and it is laughable to say that it is outdone by BG1.
Also, saying "is outdone by BG2" is pretty hilarious. If it outdid BG2, it'd be my favourite game. Not being my favourite game of all time doesn't mean it can't be excellent. And it actually does outdo BG2 on the vast majority of fights - just not the key fights.
My point about encounter design in BG2 wasn't that BG2 "outdoes" PoE in that regard. I would have been amazed if PoE matched up to it in that regard. It's more that it doesn't even remotely come close. As much inspiration as Obsidian took from the IE games to make PoE, they seemingly took no inspiration at all from BG2's encounter design. While some of the things they left out that BG2 fans are mad about can be argued that maybe they aren't actually that good, it's not controversial at all to say BG2 had great encounter design. It's one of the key reasons it's a great game and why people even wanted a spiritual successor to it 15 years later.
Though frankly this is a problem with RPGs in general. For as important as encounter design is, designers seem to put very little effort into it in most games. D:OS and Wasteland 2 weren't very good at this either. I don't really get it because it can turn a game with less than great mechanics (like BG2) into an exceptional game if done well, and can similarly destroy a game with otherwise great mechanics (like ToEE) if done poorly.
As for BG1, the only thing that's laughable is you saying it's laughable that the encounter design could be outdone by BG1. I can see an argument for PoE being better in this regard, but it definitely doesn't blow it out of the water so much as to be laughable to suggest otherwise. Encounter design in PoE is mediocre
at best. I think you're mistaking enjoyability of trash combat with encounter design. Yes, fighting groups of ravaging kobolds is more entertaining in PoE than in BG1. The encounter design, is, however, the same. "Let's fill this entire dungeon with kobolds" isn't suddenly better design because kobolds have more HP so you can't just wipe them out with a fireball. The fact that trash combat is more fun in PoE doesn't make it not trash combat.
If they build on this game BG1 -> BG2 style, we have great things in store.
I do agree with you fully here. PoE is already a better game than BG1, so if they can make that kind of leap it would be amazing. I just hope they understand what they have to do in order to make that leap, and, personally, better encounter design is at the very top of that list.