I suspect this is largely a negotiating tactic from the biggest clubs aimed at changes to the Champions League, so hopefully will disappear as a suggestion soon. Albeit I image that the outcome will be no European Super league but with the biggest clubs having greater influence over the Champions League, so still putting more power into the hands of the biggest clubs.
The only problem with that theory is that the big clubs have already won that battle, I believe. UEFA is due to announce changes to the CL either today or tomorrow that will put more power in the hands of the big clubs (i.e. those likely to do well in the CL).
In a broader sense I've no issue with a European Super league - indeed isn't the Champions League already this. The big issue being that there is no 'relegation' and therefore no promotion. So no other team can get in on merit. That seems inherently unfair, but will also impact on quality and competitiveness - if there is no downside for losing, where is the motivation later in the tournament where teams can't progress but will be back again next year regardless of their results.
All that is true but also, this super league would contain only twelve clubs determined by their financial clout rather than current form (as evidenced by the fact that Arsenal and Spurs are involved). It's certainly not fair but I think the biggest objection is that it is an attempt to syphon off as much of the European football revenue stream as possible into the pockets of the owners of those twelve clubs.
ETA: I think this will die before it gets off the ground. If the twelve clubs get expelled from their respective domestic leagues and banned from European competition, it'll kill them.