Gearbox and Sega would gain a lot of respect back if they did release an SDK, even though we know they won't. But a compromise I see is to at least release the SDK after they've finished releasing DLC, then the game won't die. The fans would make this game the tits!
But it's useless talking about it though. This franchise, and the companies and people behind everything that comes out lately, is just utterly f**ked up.