I understand people's concerns about the round robin producing dead rubbers and lack of interest. One solution I could see would be introducing a route back to AI series plus an intermediate competition.
Beaten provincial quarter finalists (17 teams) all go into round robin, 4 groups, seeded on league standing.
1st in group advances.
2nd and 3rd go to TC quarters.
Beaten provincial semi finalists (8 teams) plus 4 group winners do a round robin of 4 groups (2 games). Should be not much waiting around for games as defeated SF's can play each other while the last round of other series is being completed. Top of the group plays beaten provincial finalists for place in AI QF. Other 2 in group play in intermediate QFs.
Fixture congestion could be an issue (teams might have to play 9/10 games if they advance far enough), but maybe tweak the league. 5 divisions?