Sand cut bolt pic.
1st, I am confused about why you did not detail/explain how a FAL is "field stripped", and how it is easily the simplest rifle to "open up" to remove the bolt/bolt carrier and access it's internals. A lever on the upper rear of the "upper receiver", just like the lever that opens an over/under and/or a side by side shotgun, is all that is needed to "open" the FAL, (pivoting open like an AR). The bolt/bolt carrier can then simply be pulled out by the attached hinged rod that serves as the contact point with the recoil spring housed in the butt stock, (Think the hammer stirrup on a 1911 pistol). The "internals" of the rifle are thus exposed for cleaning. No tools are required for this process.
2nd, after building a "80%" AR, I see no difference in the "number of parts" contained in either rifle, nor do I see any significant difference in the tools and process required to completely disassemble either rifle. Actually, the AR/Stoner rifle contains more spring detent parts, which are far more complex/cumbersome to assemble/disassemble, BTW.
3rd, admittedly I have NO experience field stripping/disassembling other semi automatic .308 mag fed rifles, but if anyone can detail how any of them are easier to field strip, disassemble, and have less parts than a FAL, I would like to be educated.