I'm a fan of the Fed Ex Cup but it will not and should not overtake the Majors in terms of importance. There are a number of key issues
1) Fed Ex Cup is not a global event - you have to be a member of the USTour to be in with a chance - this in itself is reason enough for it never to have eth same standing as the majors - how can it be the greatest test when its not open to everyone?
2) History - its not the most important thing but the professional game, in all its guises, has been defined by the majors (how long have people been talking about Woods beating Nicklaus's record). For example I'd be pretty sure that the Fed Ex Cup won't be in existence in 10 years time, there might be a different version or a tweaked version or their might be nothing - the majors will still be happening as long as golf is happening
3) The majors are a actually a greater test of golf - McIlroy has been outstanding the last two weeks but shooting 20 under two weeks in a row would suggest that the courses are too easy. You have teh same players in the majors and far far harder courses
4) The current format of the Fed Ex Cup is about entertainment and it works in that regard - however this is a completely flawed system with regard to a test of golf, rather than an entertainment offering - for example a player, lets say McIlropy seeing as he has won the last two events, could concievably win all four majors, win the first three comps in the Fed Ex Cup, finish 2nd in the Tour Championship and not win the Fed Ex Cup => with a record like that would teh ultimate winner of the Fed Ex Cup deserve to be Champion Golfer of the year?
5) I have no issue with teh Fed Ex - its entertaining and generally produces good golf by leading players - lets just leave it at that (matchplay idea is crazy).
6) The Fed Ex will never produce a winner like Todd Hamilton, Rich Beem, Ben Curtis, Paul Lawrie, Darren clarke - and teh majors are all teh more appealing for doing so