I thought the reason it wasn't held in summer was because of local monsoon seasons. Wasn't it mainly changed to stop big European clubs from bytching every winter?
With the tournament expanding, you'll get a better TV audience in the summer then in Jan-Feb.
Also moving it to the summer, it should cause less mistrust between the Players, National FA's and Clubs. With it now being in the summer, NO ONE has any excuses.
Take the Matip situation, where he hadn't played for about 18 months, decided to retire and Cameroon FA still called him up and got him banned from playing for Liverpool.