I don't really see the need to be honest. The new system while being a bit tough on newbies seems the simplest way to go without being incredibly unfair. Everyone wants to be playing the GS and MS, but common sense dictates this can't happen.
Increasing the points from challengers seems a more sensible option to give the game more accessibility to newbies who, in time, will help the game just as much as the established players (hopefully).
Wildcards, if introduced, would have some practical concerns:-
Limitations - Undoubtedly going to be complaints from those who run out.
Ineligible players - Those with high enough rankings that they don't qualify for wildcards, but are boderline for direct acceptance.
Issue: First come, first served is a case of luck with whoever is online at the time.
By country: Americans benefit far more than others. Disparity based on geography so is no more fair than a system with no wildcards.
By tournament organiser discretion: Lends itself to preferential treatment as deciding who gets in and who doesn't is entirely subjective.