And giglamesh, I think you completely missed the point of sexbad's critique (at least based on your post). Granted the biggest flaw in his video was that he didn't emphasize his point enough (or even clearly articulate it until ~11" in tbh) but still. You're missing the forest for the trees, buddy.
The level design? I'm aware Doom 4 has inferior level design, and actually do think sexbad articulated his explanation as to why, well there. But the overall point still stands. The level design of Doom 4 is serviceable for what that game is going for. Just like it is in Serious Sam. Not all shooters need labyrinthine level design. His video was a direct comparison between the two, so I'll at least credit it for not being titled a 'review', but this notion that something needs to be the same as its forebears to be good, is something I find to be complete nonsense, and it's something that gets brought up all too much in modern gaming. I mean I do think mainstream modern gaming is mostly garbage, but I give credit where it's due.