I was thinking because some airports have just a single gate that it's a race to whoever get's there first if anyone does. What if instead of leasing gates, we went to a slot system which is honestly closer to real life. This way an airport with fewer gates, especially ones with only 1 gate can get more flights and more competition. One airline could lease a single gate which is 50 slots right now but only use <=7 of those slots. Or even an airport with 3 gates could have 3 different airlines flying there, but again using less than 7 slots of their total 50. You could even apply this to international routes where a lot of the time an airline may only have 1 gate but uses 7 or fewer slots. Based on this, I think moving to a slot-lease system would be better than a gate-lease system.
This also brings the idea of gate sharing either by alliance partners or just through common use airport gates. Maybe there could be a hybrid system where if an airport has more than X number of gates, airlines can lease the gates for themselves with while keeping an X' number of gates reserved for common use and then for airports with less than X number of gates, all their gates are common use and shared among all airlines flying to the airport.