Elaborate where I am nitpicking? Also I am referring to all ranks, not just the very top.
If they bring the feature to ground, being able to downtier a Tiger II P or an IS-2 (for example since they are around the most played BR range), to below 6.0, is gonna wreck balance. Even if you uninstall a bunch mods outside of the strict necessary like FPE, Parts and Crew Replacement, a Tiger II P and an IS-2, is still gonna be significantly better than something like a Comet, or an uptiered T14 or T-34-57, even more so on maps with long LoS that benefit the KT and IS2.
If there wasn’t such drastic performance differences between vehicles, BRs wouldn’t be a thing and you’d have just Rank based MM, which in itself is really shoddy due to how basic and inaccurate it is compared to individual BRs within Ranks.
And regarding your example (which is more nitpicky because it’s a what about focusing on top tier alone), you can strip an F-15E of it’s fire and forget armament, strip it down to just the Vulcan and make it fight 11.0s+ that have smart armament, it still is an F-15E that is gonna mop the floor with a MiG-23 on performance and defensive capability alone.
Same with stripping a MiG-23, still gonna outperform something like a T-2.
Or an F-106 at 9.3 which is already extremely good, going lower to more reliably fight 8.3. A Sabre A-5 to fight Me 262s and so on, really. The props are the ones with the least major gap of performance between BRs and Rank, until you get to early 109Bs fighting slow biplanes.
War Thunder is 1.0 to 15.0. That is a much larger gap that you have to account for than just Rank 8 and 9, and as Gaijin said, if they expand this system to Ground, then maybe ships, helicopters, boats and whatever else they’ll add, now you have to rebalance game from scratch to avoid having vehicles that are gonna overperform or underperform, in an easily abusive system.
This is what I mean by this being a Pandora’s box situation.

