Well there, Mark......
1. Elbow pads are available for those who choose to use them. (I've never needed them.)
2. Mounting a seat with backrest invites tipping over backwards, but many install them anyway. (Never needed it, never wanted it.)
3. Once a shooter plops his weight down on these benches, the shooters own weight preloads the entire assembly, making them as stable as a fixed multi-leg bench. Really.
4. Before criticizing the design with no experience whatsoever, perhaps you may want to consider actually shooting from one of these units then list your gripes based on what you actually gain from the time spent on one.
As of this year, I've spent 21 years shooting from my personal bench of this design. That's hours and hours, days and days.....21 rat shooting seasons with no fatigue, no raw elbows, sore arse or any other malady, just memories of great shoots and good times with my friends.
Jus' sayin'......