I just don't like the fact that I've driven a long travel I beam Ranger and an A -arm Ranger, I've worked on both of them doing several serious projects on my friends A -Arm Ranger, and I could see a 98 driving down the freeway and say to my friend "Hey, check out that 2nd gen" and he could reply, "No moron, that's a 3rd gen, don't you know anything about Rangers?"
If you can't tell the difference by looking at the body from most angles, it's stupid to grant the model a different generation just because of a suspension change. Because as you stated, different sub-models within a model have different suspension setups. No one refers to a Sean's Mustang as a different generation than your Mach beause of the IRS. And no one, refers to a torsion bar Ranger as a different generation than an coil A -arm Ranger, so why refer to an A -arm Ranger as a different model than an I -beam Ranger?
In closing, when my buddy and I go to the junk yard looking for a tailgate for his 2003 ('3rd gen') Ranger, we'll be looking for a 2nd gen truck (93-03).
