I've kind of liked the idea for a few years now of leaving subs alone and switching to three 30 minute periods, instead. We've kind of tip-toed into anyways with the amount of game stoppages that have proliferated over the past few years.
I think the players and coaches would benefit from a second rest period, and then maybe additional subs wouldn't be required. Minor injuries or knocks could be better assessed and managed, additional tactical instruction or correction could be relayed. On the business side, ad revenue would increase so there's an olive branch there to hopefully ward off the corrosive demands for fixed leagues, etc.