It not just about writing new Plugins from Scratches. We need single plugin for every type of feature, Ad, IAP, Leaderboard etc.
I am fed up of having 1000s of IF condition to use a particular feature. I am forced to mintain different versions for iOS (Game Center plugin & Admob, Cranberry IAP), Android(Google Play & Admob, Cranberry IAP) and finally Windows (Pubcenter, Offical IAP and no leaderboard!)
This is teh issue I have brought up in my new Topic: