Going off the current football calendar. With the internationals fortnights it's basically games every week up till Christmas. Which means all the domestic cups start will have to be moved to into the new year and there will be no midweek league games from Sept-Dec for teams in the CL/Europa. So yeah like Liu said the league's are going to have to start at the beginning of August. Looks like the PL CL teams will be exempt from playing in the league cup for that season.
The fixture congestionapart from PL because I just don't see a majority vote for 18 team league even tho they should. I can see Italy and Ligue 1 moving to 18 teams. La Liga will depend on the T&C's on that investment money they took.

Maybe if the knockouts in the CL went to single leg this wouldn't be so bad ... but this is crazy. Almost makes me surprised they ever went away from the 2nd group stage that they used to have.