I don't doubt that Sam re. less clubs and travel logistics for some clubs. At the same time the FAI should look to cater for the A Championship clubs who've been looking to progress.
There should have at least been a meeting between the FAI and all the A Championship clubs to discuss a number of options. While far from ideal, even only 6 clubs could make up the A Championship played over 4 series. It would provide 20 games, 6 more than the 14 this year.
A national A Championship might not work for Finn Harps, but I would think 3 or 4 teams would field a reserve team. Only 2 or 3 first team clubs would be needed then.
The A Championship clubs possibly have not done enough anyways. Over the last few years, they should have formed an A Championship board with each club having a member. The A Championship board then should have liased with the FAI.
On clubs who could take part in a national A Championship. I think Castlebar and Tullamore could've stayed on board. Castlebar, Tullamore, Shamrock Rovers A, UCD A and Limerick A are all clubs who would likely take part. I haven't mentioned any of this years first team clubs in the A Championship. Only one more club would be needed for the at least unideal 6 clubs over 4 series.