It virtually sidelines the 50 over game. So much for building on the World Cup triumph. It will continue to Americanise cricket towards a more baseball like game. It ignores the County based history of the game and I hope it fails miserably. Although according to the marketing blurb being put out "it is already a success."
Other nations notably India with their now mega bucks absolutely massive and now virtually iconic domestic IPL competition disgarded their traditional ranji trophy 'county' structure (or in their case regional and state organisations) in favour of a franchise system - the success of which is self evident.
Other countries Australia, Pakistan, South Africa, the West Indies have all followed in their wake, for the most part discarding state teams (except West Indies) and introducing a franchise based tournament. The Australian big bash being the most lucrative.
New franchises often invite suspicion as disregarding the history and traditions, these developments can often further progress not hinder it. T20 was frowned upon, it still is by some die hards but commercially its literally ensured the financial stability of the game.
The hundred is not the same granted, it's a new development and like every new development is a sitting target to be shot down before it even has a chance to maybe prove worthwhile.
The obvious disadvantages are so obvious that the situation is unlikely to be continued for any real length of time, the calendar is likely in time to be transformed as the fifty over competition will only be allowed to wane if it starts affecting the national team.
It's no coincidence England reached the world T20 final last time and but for a disastrous last over and remarkable six hitting from Braithwaite would have won. The T20 team under Morgan is now extremely formidable, in many ways the skills picked up at T20 have made the 50 over game just a longer version of T20 for batsmen, especially on flat wickets.
England's white ball success has come about in both forms of the shorter game and it may be sustainable even with a domestic 50 over competition only involving younger less high profile players. I actually think the 50 over competition will be reformed again and become more prominent once again with domestic calendar changes in the future.
Changes to the domestic structure of leagues and when each competition is played happen on a regular basis and won't suddenly stop happening.