People claim forge is an API but I really don't thinks so. All it does is manage the conflicting parts of minecraft to really do anything you must reach into the minecraft source. I propose that we make an actual API that encapsulates the minecraft source code, much like bukkit. The difference in my mind between forge and bukkit is that with forge the majority of the burden is on the bukkit team while with forge the majority of the burden is on the modders. I absolutely adore forge, but one of the problems is incompatibility between mods and minecraft versions. with bukkit there are three layers: NMS, craftbukkit and bukkit with craftbukkit implementing bukkit. I propose that we take a similar approach and create a real API that modders can use without touching minecraft. There are 100s of dead mods out there and 100s of dead plugins, funny thing is, most of the plugins still function. I would be willing to help with this new API if implemented.
Long Live Forge!