Copy/pasting my comment from that video:
"To be fair, the hate comes from multiple different directions including the whole 'people felt cheated' thing. I mean, during the lead-up, we had a brick wall that had strong SR1/SR2 vibes what with the graffiti and all, then we got this CGI trailer with zero gameplay. They felt manipulated because Volition seemed to be telling them one thing and we got something completely different. People already hate change, especially when it concerns something they love dearly. So I can get where they're coming from there."
That said, I do agree with the other parts. Volition wanted to do something new and honestly, as much as I love the OG Saints, I'm down for it. We spent five games with them. There's only so much you can do with them. Were there missed opportunities? Sure, like the whole Dex thing. But they missed that way back in SR3. Hell, they even missed that opportunity in SRIV when they could've had Dex lead a terrorist gang and Boss, as the POTUS, fights him throughout the real world and cyberworld.
Point is, it is what it is. They probably realized this as that's why they're starting fresh.