■Dome shields suffer from the same basic issues as the spawn room shields, i.e. the collision doesn't render at extreme ranges on your client, so you can shoot past them. With AOE weapons this creates a big problem - one that sucks a lot for spawn room shields right now, but would completely invalidate the purpose of dome shields. Fixing this is a priority for us right now, and while the fix isn't very complicated, the impact on performance and resultant subsequent changes create a pretty complex problem.
■It's only 'abused' by a few players, sure, but the real issue is that it's unreliable to the people it's supposed to help. It's obviously not prudent to be implementing more features on the back of an already broken mechanic that we know we need to fix. Once it's fixed, you'll likely start to see more info on dome shields.
■Once we have the shield/distance issue solved I can see a couple potential implementations for these.
1 - the large facility level shields, these would likely be limited to Amp Stations and the upper floors of Towers (not the flight decks) and associated with two requirements, a gen at the base itself for the shield which can be overloaded and connection to an Amp Station (which friendly amp stations would always have, obviously).
2 - Engineer deployed dynamic shields, smaller shield domes that would create a shield arc a few meters up in the air with maybe a 20-30m radius. These could be used to create cover areas around sunderers and spawn rooms.
■Yeah, it's really painful. I personally play 3-4 hours a day as a pretty much 100% dedicated infantry player. I get it, trust me.
We've discussed some solutions like you suggest, and I think they're still open possibilities to help fix the issue more immediately with spawn room shields. If possible we always want to fix the real bug not implement some weird, potentially unintuitive rules to work around it, especially if we're adding something brand new like dome shields.