@JamesBon92007
It was my 12 year old nephew who got me into diving and we started in jackets BCs. Shortly after we were cut loose as AOW dives, I switched to doubles to have more gas for both of us since we were both serious hoovers back then.
Of course, my nephew wanted to have a similar look and got a regular BP with an Oxycheck wing and single tank adapter. It took him less than 15 minutes to get used to the hip dump on the wing and to realize how much nicer that is. He never looked back and wondered why we even messed with the jacket BCs.
My guess is that it is easier to take a jacket BC off the rack and throw it on a student's shoulders rather than adjusting the BP webbing correctly (once). Plus they can sell you two pieces of gear that way.
Functionally, the BP/wing is superior in every aspect and if you follow the Hogarthian/DIR approach it gets really beautifully simple and functional. When I got instabuddied with someone who had never seen this setup before and briefed them on how they get gas and where all other items can be found the comments were always along the lines of "Wow, that's slick. Why doesn't everyone dive that way?" Excellent question.
As mentioned above, weight needs to go close to the tank or on the sides of the hip belt as far back as it will go. Then, you can take a nap on your back at the surface.
Another thing that could tip you forward is pulling your feet up behind your butt if they are really floaty. Try next time to let the legs hang straight down when at the surface. I have strapped literally anything from a small medical cylinder to "water heaters" holding 300 cuft on a backplate and never felt at risk of ending up face down.
That's the other beauty of the BP/wing: any environment, any gas quantity and always the same user interface. Just change the tanks and the wing or dive wingless with an appropriate tank.