It's an interesting take to be sure, but I think it is massively impractical and counterproductive in all but a very small subset of debates that it would most definitely not see as much use as for topics where it is completely out of place.
I've had an argument over the canonicity of Thunderbolt a while ago with someone who was desperately trying to fit it into the main timeline (I'm camp "why does it matter, just let it do its own thing and stop worrying about it"), and the dude went to pretty ridiculous lengths using that principle as base of argument.
"The OVA is canon, but the manga it's based on isn't"
"If more of the manga gets adapted, that part of the OVA won't be canon"
"The things that don't fit in are just somebody misemembering things, that thing that doesn't fit in with the lore wasn't actually there" (to the point of "well, maybe that person who died onscreen isn't actually dead")
and a few more like that that I can't recall off the top of my head.
It is certainly a valid idea for discussing overarching themes and other more meta aspects, but for talking about timeline, it is too messy and leaves a ton of things unaccounted for.
Assuming linear time, which to my knowledge the Gundam franchise hasn't given any reason to assume otherwise, there is an absolute truth, and barring things specifically framed as subjective recollections, what we see on screen being the absolute truth should be the starting point, because any other premise is a complete non-starter, since from that point on, every fix point and boundary set is completely arbitrary, and if it really comes down to it nothing more than glorified fanfiction.
The real problem is not that Gundam has some inconsistencies in its lore, the problem is that fans, especially western, are way too anal about wanting to have everything fit into one singular timeline, even works like Origin or Thunderbolt, which from the very start have been explicitly stated by the author to not be canon to the main timeline. The solution to this is not to disregard cherrypick the events you like and disregard the ones you don't, not to write fanfiction on how if there is a whole seperate production branch that we have never heard of that line of custom suits never seen anywhere else might fit in (line of arguing from an unrelated Thunderbolt debate, the opposing side was mindlessly yelling about production numbers, so not much better), and definitely not to just declare things we see on screen to not have happened that way; the solution is to only treat those things as canon to another work that are explicitly stated to be canon, and have everything else take place in a mental AU where details may differ.
Why don't you save the Princess next time instead of being such a baby? She would love it and maybe you could get a sweet kiss. ~ Joseki
Your point of view is horny, and biased. ~ glitz2hard
What about titty-ten? ~ Reichu
The movies function on their own terms. If people can't accept them on those terms, and keep expecting them to be NGE, then they probably should have realized a while ago that they weren't going to have a good time. ~ Words of wisdom courtesy of Reichu