Honestly, I think dominion might be the only current "competitive game mode". It is the only game mode currently that forces action. 1v1 and 2v2 and 4v4 elimination have huge problems when you approach them with a competitive mindset. Time outs result in a draw if you have equal number of players, or a win if you have more players. Health is not a factor at all. If you have a numbers advantage, it's beneficial to take zero risk, and just avoid fighting until time runs out.
Furthermore, if you are playing a character that has heavy ring out potential, such as Warlord, it is in your best interest to camp near an environment kill, so if you parry something you get a free win. If it's 1v1, neither person has an incentive to actually approach the other on terrain that is beneficial to the other. If it's Orochi vs Warlord, the Warlord can camp near a ledge, Orochi obviously wants nothing to do with that since his throw distance is butt. So he will want to hang back in open space to utilize his mobility. Neither has a good reason to approach the other in a 1v1 situation.
In addition to that, if you have a life disadvantage in a 1v1 on something like 4v4 elimination (and even some 2v2 maps), you might want to just run away until time runs out to take the draw. It could easily be the best choice, especially if your opponent is playing a slower class and has no chance to catch you.
Basically, if 1v1. 2v2 or 4v4 elimination is the competitive mode, expect these strats, which IMO would be very detrimental to the game.