recently I tried testing which PD + wall template is the "best" one and, to my complete surprise, I found that their effectiveness varies hugely between the factions.
In short: Aeon PDs become immortal to t1 tanks when surrounded by walls, Cybran and UEF PDs get a slight HP boost, and Sera PDs don't seem to benefit at all from walls.
Links to a couple clips I made during testing:
For testing, I surrounded the PDs with an assortment of t1 tanks of all factions on the Seton Landbridge. The tanks are shielded so that the tank, PD and wall positions are exactly the same for each test. (Testing replay ID: 14204602 (very long))
Additionally, it seems that it's not just the PD or the wall hitboxes that result in those highly variable results:
Surrounding a Sera PD with Aeon walls still doesn't help the Sera PD survive at all.
An Aeon PD with Sera walls does benefit from the walls, but doesn't survive nearly as long as with Aeon walls.
What's going on here? Is this well known? Intended? Should one just never build walls around Sera PDs??
Solution idea to conform to the guidelines: I think we should change this behavior and make the effectiveness of PDs behind walls at least similar for all factions by adjusting the hitboxes of walls, PDs or both.