We have no *immediate* plans for GSX to control jetways, but it's something we'll deal with in the future, since the default FSX system is not very smart.
There are several other threads that suggest how to use GSX together with AES, you'll find them in this forum.
The compatibility between the two will be surely increased when AES will be modified to allow to choose whether to have its own vehicles automatically appear as soon as you select a parking or not, and when AES will be modifed to choose whether you want to use its marshaller or not, like GSX allows now.