2 vs 2 requires team work and familiarity with what each kind of unit does, especially those you rarely use in your deck. It is easy to spot if there is synergy between two teammates or not. And once your opponent sees this, they can easily take advantage of the situation.
The only thing I hate about 2 vs 2 is when your teammate goes offline - perhaps because of a lag in his internet connection, and you are forced to handle two players on your own. But I guess it is part of the game, but I wish there was a way to level the playing field when this happens, maybe allow you to control your opponent's deck, too, just to prevent from being overwhelmed by two player's combined forces.
It would be amazing to see if this game can expand to 3 vs 3, 4 vs 4 or even 5 vs 5. You would probably need a bigger map. And I don't know if you would then be forced to focus on a single unit - then it would be too much like DOTA.
But the Clash universe has already made a big investment in getting their characters recognized, that might just be the next step when Clash Royale losses steam. Still, for now, 2 vs 2 is too fun to pass up. Wish the tournament for 2 vs 2 always has a free entry, that was, I don't have to waste gems on losses. It's already a tough environment, I've yet to get to 10 wins. But it's really lots of fun, and if I could forego the payment of gems, I'd be more willing to experiment with my deck combinations instead of sticking to tried and tested ones.
Thank you, Clash Royale development team for coming up with ways to make this game better. May the game play continue to improve.