I would like to suggest that you would have a test mode where you can take any 4 troops, have them max level and fully traited and test any team setup against some random bots to see how well they play. Because they are fully leveled and traited you would receive no rewards/ gold, traitstones etc but would at least have a way to try a team setup.
The reason i suggest this is because it is very discouraging to try new team setups considering how difficult it is to level up and trait troops. I feel the game can grow stale when it encourages me to keep a same safe team setup until it is leveled.