No argument the straight line buffer creates other issues. But, the point it, that a firearm has to accommodate the fact that our line of sight, and line of stock is separated by about 5 inches. So if you straight line the action, it lowers the barrel and the sights have to be elevated. If you raise the action by dropping the stock, you can get the sights right down on the barrel - but you also create a recoil issue, the stock rotates up into the cheekbone.
That means the straight line action is perceived as having less recoil than the dropped stock version. There are tradeoffs, Stoner chose ones he felt enhanced the user's ability to get back on target sooner with less muzzle rise and a more "user friendly" feel.
So, the straight line stock has it's advantages, too. If you are firing 300 rounds a day in combat, recoil and it's perception is exactly what the design is meant to reduce. That was a significant factor in shooting the .30 cal battle rifles that preceded it, and why firearms makers were moving into straight line actions in intermediate cartridges long before Stoner adopted it. Don't forget, the AR15 was originally the .308 caliber AR10 first - which has 150% more recoil in terms of foot pounds of force, 15 to the 5.56 at 5.
Look to the bolt actions that grew Monte Carlo cheek rests, the attempt was to get the head up and not have the cheekbone angled downward into the stock. Doing that, the feel of recoil is directed away from the skull and perceived as "less." With magnum calibers, you don't seem to get smacked in the face as much.
The art and science in stocking guns goes a lot more into the perception of recoil than we think. And how we grip a wrist - or a pistol grip - has a lot less to do with accuracy in a rifle than a handgun. It's held by the shoulder and off hand, the finger hand only has to pull the trigger straight back.
Had ARES copied an action with the cycling springs in the action or over the barrel, then any stock, including a folding one, would be possible. That's been done a lot with piston AR's, and it works with the AK, too. Most bullpups require it.
So, what's the point of them coming up with a complicated angled action spring when it's really unnecessary? And why copy a traditional stock in polymer when it's really not necessary? A stock only contacts the user at the shoulder and cheek, any where else it's dead weight and the wood stock design actually is less efficient. It's a triumph of styling over function in a lot of respects.
I'd rather shoot my functional straight line stock with "absurdly high" sights. It's as ergonomic as any other, more so because it's more modern and some thought was given to it, not simply adopted because tradition made it so.
Man, that rifle above would be sweet with an integrally suppressed barrel 
