Opti_You make 5cps with round limit to 3 or 4. You set round time to 5 or 4 minutes. If last is capped, team who caps gains 1 round. If no one caps, at the end of the round timer, whoever has mid wins 1 round.
The big issue with a 5 minute round timer and whoever has mid wins after, is that it puts a huge amount of importance on mid fights.
Let's say it takes a team a minute to win a mid fight, and another 30 seconds or so to get their spawns and get buffed on second. The enemy team now has 3 and a half minutes to push out of last, cap second, and cap mid. Throw uber disad on top of that, what if the enemy team uses their uber to just pick up some frags and backs out again? Now you've got less than 3 minutes to wait for spawns, organise a push, and cap two points.
I think it would just make for boring gameplay of extremely passive mids and teams !gg'ing after losing the mid fight.
edit: on a similar note I really dislike ETF2L's current golden cap rules, where if the golden cap lasts longer than 15 minutes the round is reset and whoever caps mid wins. Its a decent solution to avoiding hours of gameplay, but there's more to the game than mid-fights and boiling a match down to a mid-fight feels like a cop-out.