None of the issues your reported are GSX problems. johndrago explained it already so, no need to repeat and no, nobody has ever reported a problem like that on the push-back.
As explained many times on the forum, but also on the manual, GSX doesn't know anything about the surrounding scenery, its knowledge of the outside world if provided by the AFCAD AND an eventual airport customization file you can create.
Conflicts with AI objects can be minimized if the scenery AFCAD comes with proper vehicles taxiways, because GSX vehicles use them by preference, but it there aren't any, they must use regular taxiways. Most of the default sceneries have dedicate vehicle taxiways, but many 3rd party scenery don't so, if ground vehicles and AI have to share the same taxiways, conflicts might appear more often.
In addition to having a proper AFCAD, it's possible to act on the scenery customization feature to change some things like vehicles starting positions, to minimize the chance for them to run into scenery objects, and the marshaller distance, to minimize the chance to have a marshaller ending up inside a building.
Sorry to say this virtuali, but I've seen far much less problems or isses with AES than I'm seeing with GSX even when including the pop ups with AES..
You really doesn't seem to understand. Since NO AES vehicles comes from afar, but they ALL POPUP CLOSE TO YOUR AIRPLANE, it's fairly obvious you won't see many conflict with other objects, considering they only have to move a few meters from your start position to the airplane door.
And, of course, since AES doesn't follow any arbitrary AFCAD, for example in the Pushback, but works only on its supported airports, it's always customized to that airports, similar to those FSDT and Flightbeam airports we give away for free, but with AES you have to pay dearly for this customization.
Do you have the same issues on an FSDT airport ? That would be a proper comparison, except that fully customized airports in GSX are free.