I actually liked the Egyptian theme, but then thats always been an interest of mine. The monster designs were dopey, but they had a child-like charm to them. I wouldnt change the harpies, headless bomb guys, or the bulls for anything.
They were just fun games.
I agree with your "Doom like" rant, though. Doom had lots of things to kill, but Painkiller and Serious Sam aren't really like Doom at all. Not saying that style isn't fun, but to say its "like Doom" is actually kind of insulting to what Doom did. People aren't remembering what Doom was really like to play. It was more than a killbox.