Lots of hate in this thread.
So I play Dominion quite a bit. The last 35 out of 40ish games I played were Dominion, because I enjoy the mode. Almost all of those games were wins with Shyvana. She's surprisingly good in Dominion.
Anyway, there's a lot of misinformation in this thread.
I see the same champs every game - Actually you don't. I play Blind Pick, not Draft Pick and surprisingly there isn't a Rammus every game. Jax, Akali, and Poppy aren't dominating every game. I actually see a lot of very diverse teams in Dominion. Lately the most common champs have been Ezreal and Kassadin, and I've seen some very, very scary ones. Ironically, most of the people who complain about "X is in every game" are actually the people who play Ranked Dominion and ban those champions because they're too afraid to face them.
Dominion is mindless killing - There's certainly a lot of killing and that is half the fun, however it's not mindless. As you win more Dominion games, you run into smart people who will ambush you in bushes. You learn not to travel the jungle when you have 3 points captured. You learn to take advantage of a strong top by ganking bot. I've lost games due to people thinking it was some sort of battle arena who didn't know how to group, siege, or defend.
This thread reminds me of a golf club full of golfers agreeing with each other over and over that Football is dying out because none of them play it. Very silly.