Dominion is an often overlooked and sometimes even belittled game mode in League of Legends. Summoner's Rift is generally thought of as the default mode/map and is used during competitive League of Legends eSports tournaments. There isn't even a ranked Dominion and Riot Games has severely neglected the playlist. For these reasons, some players call Dominion a "noob" game mode, but even with all that working against it, Dominion is still better than Summoner's Rift. Here's three reasons why:
1) Dominion is faster paced. When you play a game of Summoner's Rift, the first 20 minutes are usually spent walking around in circles and last hitting minions. Farming minions for gold is equally as important (or even arguably more important) than actually killing your opponents. That is pretty stupid. A game shouldn't be decided by who is better at farming minions; it should be decided by who is the better player.
Dominion games are much faster paced. Farming minions is not a viable strategy in Dominion because the object of the game is to capture and hold more control points than your opponent (there are five total so generally that means at least three must be under your control). Standing around last hitting minions isn't going to help you capture or defend a point. Minions aren't a good source of gold either because you already earn increased gold per second. You can utilize them to help neutralize and capture enemy points but you'll want to clear enemy minion waves as quickly as possible to do this, so you won't be spending time walking around in a circle to last hit them. Killing minions plays such a small role in Dominion, each player's CS is not even reflected on the scoreboard.
The average length of a game on Summoner's Rift is between 45 minutes to an hour (according to posts on the forums, anyway). The average length of a Dominion game is between 15 and 20 minutes. The first team battle in a typical Summoner's Rift match doesn't happen until almost half an hour in (unless you invade the enemy jungle at the beginning, but an ambush isn't really a team battle, either - see reason #2). The first team battle in Dominion happens within the first minute. Which sounds more fun to you? When you consider the fact you can complete an entire game of Dominion in just the "minion last hit phase" of a Summoner's Rift game, it suddenly becomes apparent just how slow and boring Summoner's Rift truly is.
2) Dominion takes more skill. Despite being called a "noobs" mode by some, Dominion actually takes more skill to be good at. Summoner's Rift is all about ganks and ambushing your enemies. Popping out of the bushes to kill someone before they can react or escape doesn't take skill because they never had a chance. It is especially hilarious when you see an entire team standing there in a bush and then ambushing an enemy that walks by. Do they not realize how ridiculous they look?
When you ambush someone, you are basically admitting that you cannot beat them in fair combat and so must resort to using guerrilla style tactics. Killing someone or winning the game does not prove you are better if you used such cowardly tactics to do it. The Vietcong were not more skilled, better trained, better marksman, or better equipped than the U.S. military but still won the Vietnam War by using asymmetric warfare. That's what you're doing when you hide in the bushes in League of Legends. You're being a Vietcong.
Ambushing people is not as effective in Dominion. There are bushes in the middle of the map, but standing there waiting for someone to walk by is not a good strategy because you are just wasting time that could have been better spent capturing an enemy control point or defending one of yours. The respawn timer is a lot lower in Dominion than it is in Summoner's Rift as well, so killing someone in the middle of the map will not help you complete the game's objective since your enemy will respawn fairly quickly. The only way to beat your opponents in this mode is to actually face them like a man and overcome them in battle.
Another reason worth noting why Dominion takes more skill is that you can't become fed by last hitting minions (see reason #1). You have to actually fight and beat your opponents.
3) Dominion takes more teamwork. You need to use teamwork to win a Dominion game because it is objective based. One could argue that teamwork is also necessary in Summoner's Rift to coordinate ganks and the like, but it is possible for a "fed" individual to completely dominate a Summoner's Rift game pretty much by themselves.
It's not possible for one person to win a Dominion game. It is possible for players to get 20+ kills with the most control points captured in the game and yet still lose because his team didn't work together as well as the other team did. When was the last time you saw someone go 20/0 in Summoner's Rift and still lose? I'd bet never. The fact of the matter is, one person can only capture a control point so fast. You can't be everywhere at once. You need to be able to rely on teammates to defend certain areas.
Saying "bot mia" or "can I get a gank" on Summoner's Rift is nothing like the level of teamwork required to win a Dominion game.
Disclaimer: Unfortunately, it has become commonplace among gamers today that if someone has a different opinion than their own or doesn't like something about a game, they must just suck at that game. First of all, I am a level 30 with around 1,000 total games played. I should also point out that at the time of this writing, I am 93/10/88 in my last 10 games of League of Legends. Click here to see a screenshot of my recent history from lolking.net. I have a winning record on Summoner's Rift (though I will admit it is only a few more games won than lost) and have beaten players ranked Gold and Platinum according to their lolking profiles. Clearly I do not suck at the game.