There is nothing to fix/change and heres why:

1: Materia prices are players fault not SE:s
2: Its free of choice to pursue relic or not, soldiery weapon is more then enough to do any content in this game right now and there will always be weapons to go for that dosnt require massive amounts of grind/time/gil in the future.
3: Spiritbond your own gear, if you got gather/crafting classes its gonna cost you nothing but time.

And alltho id agree that 75 materia would be enough and that the % chance to fail wasnt needed, its not something that SE could just change now cause that would cause endless rioting from those that already went thru the pain (me included).