I can't really see the point in the format change. It could be to soften people up for another attempt at a super-league.
The bigger issue is the expansion of the CL itself, to the point where the name is a complete misnomer.
It's not for champions any more, which means there can be a group of teams at the top of each league who can, with careful management, qualify year on year. The money generated from that qualification helps keep them up there and the importance of getting or staying there means that a Top 4 finish is an important minimum requirement. Wenger was chastised for saying it's like a trophy, and rightly so, but it has become a disproportionally important thing