I honestly think a good roaming comp is, Soraka + Amumu + Fiddle. SO MUCH MR Shread and Soraka top means you usually win team fights. As roam you get a 3 second fear, lots of aoe, and disables. Soraka can give insane AR too combined with double WoTa, its just plain broken.

The role of bot lane is to pressure their turret, not necessarily take it.

In other words, if it costs you an extra person bot to take their bot turret, it's not really worth it. Bot bot is very easy to take back. No matter what two champs you have.

The 2 bot is not a "meta". I have seen it happen sometimes later in the game, but it is not that effective.

More than having 2 "ideal" bots, what you need for this meta to work is 3 ideal tops that can work well while being outnumbered(Which shouldnt last long if bot is doing their job), or 1 bot + 1 bot roamer fast enough to be in either bot or top but isnt banned in 99.9999999% of games.

Why? The support actually gets money in Dominion, so they will be built mage (probably tanky) and be trying to kill people, not 'gold/10 I'm completely useless except to ult once late game' support.

If 2 people take and hold the enemy bot, it will take 3 to take it back if one person has a garrison. Had a game a while ago where Graves and Sona stayed bot most of the game. My team consisted of people who think like that and refuse to send more than 1 bot. They might occassionaly try to take it back in force, but then leave to avoid the 'prison slot'. Bot constantly got taken, chaos and rage at the poor ******* trying to hold off Graves and Sona 1v2 (me of course), we lose horribly since the enemy does not need windmill to win. It works, people just refuse to try anything new and do the same thing 300 games in a row.

I duo queue with a friend, and we usually use this tactic when top is going badly. Our team rages at us when we do it, even if it's working, so we've sorta stopped doing it. Fave combos that haven't been mentioned already were Ahri + Taric, Udyr + Any ranged damage and Yorick + Heimer. Really any two champs who are good solo bots will be even better duo, especially if they don't have overlapping counter picks.

After awhile people tend to just ignore a duo bot and send 5 to attack mid, which generally seems more effective at disrupting the tactic than mindlessly flinging people straight at bottom trying to get it back. Dominion is more about a good flow of tactics and counter-tactics, as opposed to there being one specific strategy that is more efficient than anything else.

sion and ahri is one of the most amazing combos I've used... we were able to hold their bottom point for so long against several of them.
ahri with rylais atleast... the slow and stun was incredible and so much fun.

Soraka + Karthus

Double stun with decent burst tends to do well regardless of who it is. Bonus points if you have one capable of long-range initiation/disruption so you can camp in the FoW near the point and catch people who try to channel.