Now it's not that I think the group stages are as boring as people think, on match day 6 they can be very exciting. But unlike the World Cup which is held in a destination is there really a need for a 12 match group, the away fans and players have to travel back anyway. And unlike the World Cup there is so much more room for error given the home and away format, one surprise result and a heavyweight could find themselves in real trouble. SAF often played kids in the group stages it even caught him out once against Basel which served him right. I would much prefer a 64 team straight ko completion, with the 16 highest ranked teams seeded and domestic rivals kept apart. Anybody else agree or am I crazy?
I suspect a lot of this comes down to money. More revenue is generated with the additional matches that a group-stage round entails. Also a club can put together their summer transfer window strategy more easily if they know roughly how much money they'll get by qualifying for the CL. If there was a serious risk that you'd only play 2 CL matches, then the minimum amount of revenue a team could receive would be a lot less. Also advancing past the CL group-stages is only considered routine work for a few clubs. Once you get past Madrid, Barca, Juve, Bayern, PSG and maybe Man City I think the group stages provide a decent challenge and no guarantee of advancement.