I also really enjoyed The Flash (up until season 6 or so when it just got too repetitive). It seems like there's a lot of people that can't seem to enjoy things "just for the fun" that I don't get.
Humanity traveling faster than light? Check. Woman using stupid bras? Check. Radar that maps entire cave? Check. It doesn’t flag a creature 5m ahead? Check.
For many, these details are unbearable plot holes. Watching science fiction require you to be able to skip these and focus on the story (girl in love, sucking at survival sim).
That is the main issue for most people. If they wanted to do their own thing for a new show, it would have been fine. Maybe you check it out, maybe you don’t. Maybe you like it, maybe you don’t. But they didn’t do their own thing. They made an adaptation of an iconic sci-fi series by one of the most famous classic sci-fi writers. They sold a bag of goods that had “Asimov’s Foundation” printed on the bag. So it can’t be too surprising when people open the bag, find it is a sprinkle of “Foundation” and mostly “generic sci-fi” sawdust filler, that they feel tricked. Bait and switch comes to mind.
Naming and marketing as Foundation is like pretending the I Robot movie was an honest adaptation of Asimov's I Robot. Foundation started well, but it's becoming a standard space opera template with Asimovian names.
Asimov wasn't the greatest writer, but he had innovative ideas and central themes that should be the core of any adaptation.