If you actually read his criticisms instead of simply going straight to sarcastic remarks, he does have some good points, although OP, I think ranting a bit too much about racial changes that are very subjective.

As for your overall idea that Act 1 was extremely good, and the quality starts to drop after that, you're not alone, many people have noticed the issues.

I also agree, the elder brain suddenly saying "lul, i tricked three gods, and was in control the whole time" is ridiculous, and Ketheric going to shar, no wait Myrkul was a bit of a head scratcher. Honestly I think part of it was just to bring in Shadowheart to the main plot. She's obviously the most important origin companion, and that was clear from very early on in EA.

OP, if I might make a suggestion, maybe organizing your post into clearer sections might avoid the ranty look of the post, and more people would be willing to read it. As it is, I'm betting most will just read the title, see the huge amount of text and assume you're just ranting nonsense.