I think a big issue is that the CL can be so random. The schedule has big gaps where injuries/form can really dampen the overall season a club is having. 2 leg ties with a 1 leg final turns chance/randomness into a bigger factor depending on scheduling and injuries as well. Premier League is so competitive because of the massive TV money and that all teams get basically an equal slice (you either outspend or take chances by paying for youth). Other leagues it takes a club with an incredible academy and/or investment/patience in a manager to compete since TV money is much lower and not spread out as evenly.