World Cup and UCL are the giants currently, but you're right. The CWC has the potential to become a prestigious club trophy if it's developed properly. I don’t know if it will be the *most* prestigious because UCL is the highest level quality football hands down.
Discussion
IN terms of quality hands down UCL totally agree, the thing with CWC is the 4in4 years, and its basically world Cup with real fans
They need to have the next one in a real football country, Brasil, Europe, turkie I don't know, but tou need more local fans engagement, and obviously some tweaks
UEFA probably sees the CWC as a threat. It's a direct challenge to the Champions League for attention and money. Doubt they want it in Europe anytime soon… as a football fan I want it to succeed.
I think you have space the game is evolving fast
For me the reshaped UCL last season also was amazing the new format Gizzzz
But honestly i think the biggest rival to UCL is the Premier League, they are oN average week iN week out, the best football oN display