@Geobound, Complexity is bad underwater. We had a student with an i3, it adds unneeded complexity, which is just a bad idea for no compelling reason in this case.
On BP/W, you can get trimmed fine in an all-in-one back inflate, or even jacket BC. Several here will tell you BP/W is not needed and their jacket or all-in-one back inflate does them fine. Apparently they are happy. And they're right, it is not needed. If you have an all-in-one dialed for you, there may be no big reason to switch. Unless you'd rather more flexible and maybe robust gear.
BP/W has some advantages. Its metal plate and 2" straps make it easy to attach small pockets of trim weights almost anywhere on back, shoulders, front, or ditchable on waist. A buddy is struggling trimming his jacket BC -- without turtling from weight placed on cam straps -- as he has few other attachment options. I'm working with him, but 2" straps and a nice plate to attach anything would make it much easier. Also, if you have a *lot* of weight, a steel plate can put part of that weight right above your buoyant lungs, while still keeping some free as trim or ditchable. BP/W has flexibility of weight placement, wing size, and customization with anything that fits on a 2" strap. All the components -- plate, wing, webbing, weight and gear pockets -- have extremely loose interface needs -- usually just 2" webbing -- allowing sourcing or replacement of components from many manufacturers! Metal plates, industrial strength webbing, and metal hardware are really robust. As a bonus, PB/W are often inexpensive.
ScubaBoard does not represent the general diving population, it certainly spends more time and focus on the sport. That might represent a more researched and possibly experienced take on issues. From reading, you'll see many here dive BP/W. Take a read through the BC sub forum.
On being pulled face forward, I've only experienced that when I put way too much of my weight on the front of my weight belt and harness. I only did that briefly, as underwater it make it hard to roll to the side. My keel heavy front kept rolling me back to point down. With my weight better distributed front to back -- how I want to dive anyway -- I've had no issues on the surface, in the ocean and with beach surf entry/exit. I can easily back/side/front surface swim, or better remove the rig and use it like a mini raft to paddle along looking about.