Since the early game from summoner's rift is basicaly steamrolled on dominion, jax's greater weakness is removed, he rapes on dominion because of that. After a certain point he never ceases to be a threat. Same thing with poppy, whose main weakness is her laning, and since there's no real laning phase in dominion..
Some champions suffer from this though, yorick feels sorta silly on dominion because of that.
... When was the last time you saw a Yorick in any game?
I'm not sure, it'd make sense if it did. Even so, riot did a good job of stopping people from winning games just by taking all points all the time but never quite holding them. I dunno if you were with us when we played a dominion game in which the enemy team relied on an eve and TF going around taking points but never holding them for more then a few seconds. Then they lost because they were dying alot due to having 2 teamates constantly MIA and so couldn't hold the few points they were actualy trying to hold. Anyway his ult's range didn't seem to different.
Well, Eve's are pretty bad to begin with, and you'll have to rely on Twitch to assassinate people.
But yeah, you really CAN'T do that. I tried, but they eventually catch up to you, and your one-man capturing spree isn't going to work if their 3-5-man capturing team has murdered all of your teammates. Then all you have is 0-1 turrets and a really angry enemy team surrounding you. Oh, and they can see where you are and get there really fast.
Don't try it. It doesn't work on competent teams. Or not very incompetent teams.
Slap a movespeed buffer/point capper as your fifth. Rammus, Master Yi, Eve, maybe Janna or Karma, Sona, etc. The last three, especially, since they get free money instead of being told not to farm.
Hmm... Well, that's a tough call actually. They'll have just as much money as anyone else, but Supports tend to scale less with items than carries. But, I'm not against it since there are several good items they can grab that AREN'T AP or AD items, which is really nice of Riot to do. So, they can be the ones that have increased capturing rates, since they'll be capturing with teammates and what-not.
It will require testing.