This reminds me of RO mod. The Zis truck had you sit on it and you'd only die if the entire truck was destroyed. The driver however was vulnerable independent from the vehicle. At times we'd jump onto the truck rather than enter it, the advantage was you could use your firearm, you could even deploy an MG on it. The disadvantage was you could fall of due to bouncing off the truck model or rough driving.
I'd love to see the utilization of civilian vehicles pressed into military usage. A fast recon vehicle would be good for large maps. A SL could drive to strategic positions in order to mark artillery.
Back on the tank riding. Maps such as Barashka and Ogledow, even bridges would profit from it.
I in general wonder over the years I have been with RO why good achievements of the past have gone missing, need endless discussion and then still do not make it into the game.