Very good point, but i must correct you. The key has a chip which is matched to the ECU, not the antenna. The antenna is only a device used for reading the key. Therefor, any antenna will work, it does not need to be programed. To prepare for this, the the safety bolts (which can only be tightened) must be removed from the key shroud and replaced with allen bolts. This is hard to do in the field without a trill and the right bits. If and when your antenna does fail, you only need to remove the old one and plug in a new one. Alternatively. you can buy an extension wire from BMW and simply un-plug the old antenna and plug in the new one and keep it near the key during start-up. The antenna will read the key and deliver the message to the ECU, which will then decide if the key is correct and allow you to start the bike.
The fuel pump controller had an issue with the gasket on older models and a re-call was issued.
The new gaskets are pretty good, but the position of the controlled is in a very vulnerable place with minimal protection from water. You can silicone the seal, but packing an extra is a pretty good idea! In a pinch, it is possible to hot wire the fuel pump to get you home, it will run at 100% until you replace the controller.
I had a 1200 GS which i sold last year. Although it was one of the best riding bikes i have ever owned, i must admit it would be my last choice for an ATW trip due to its complexity and fragility.