Add time to later rounds, shorten time in early rounds
There's some pretty epic battles to be had late game. You have a lot of units to maneuver, a lot of money to spend, a lot of decisions to make. You also might benefit from looking at your enemy's team now that the field has been narrowed. But so often I get caught out of time, mid-move, mid-purchase, costing me a game. Having invested 30+min into a game, I wouldn't mind having more time to spend making decisions. Especially after the dragon fights, where I've rearranged 8 units to avoid his aoe, and it's hard to get them back in place.
Alternatively, you do not need 10 seconds for the first round, you cannot lose it. I always use the first 3 rounds to take a leak, get a snack, because they take soo long. You do not need all this time early game. If you shifted this time late game, it wouldn't increase over-all game length, and losers could start new games quicker.