The problem I see with the "Gateway airports" is that it protects the big airports, even in the long run, it will be easier (negotiations) to choose a Gateway vs non-gateway.
Irl many small airports (underserved) would love new foreign airlines. And in the game, it could be easier to fly to non-gateway African airports, instead of investing in the same markets.
In V2 today, JFK and LHR are Top2 due to the "favorite" Gateway airport. I think without Gateway we could have more competition.
If the goal is to limit IC flights or/and protect home markets, I understand but I feel it is protecting main airports.