Let's talk game rules that are not really game rules.

Although they did get nerfed, sunderers still have the potential of being the strongest vehicles in the game. A good driver and 2 gunners, and armored sunderer can cause quite some damage. Or a column of rep sunderers too for that instance, which is why they were nerfed in the first place. In the hands of a solo driver, a sunderer can be the weakest vehicle though. Totally agree about the bubble, its meant to protect from vehicles, not infantry, and once a light assault finds it, its dead.

My solution to making stealth sunderers better is cloak the the sunderer, like the ant cloak which is pretty good. And just make it that people who spawn there get an infil cloak for 30 seconds or until they start firing. That way they have time to get away from the spawn before they uncloak, making the spawn harder to locate. If people complain about invisible OP spawns, just make it so thermals can uncover them. Also darklight flashlights work to illuminate cloak spawns.