I don’t believe it is what it is actually doing. Instead, it makes concessions because they decided it was better to make FS2020 flying FSX ported aircraft like in FSX so that 3rd party devs could port their add-ons faster to FS2020. It is not dissimilar to what I’m saying about the FS2020 systems and gauges SDK either and probably for the same reasons as well. Given the number of “sophisticated” aircraft available and “ported” from FSX, this begs the question whether this is a good decision from the get go.
Which raises another question to me: in making their normalization algorithm "bending’ their 1000 element model to match the FSX historical flight model behaviour, didn’t they just cut out what could have made their new engine a key differentiator from the past and from competing simulators?
Because it looks to me the main difference between FS2020 and XP11 flight model is this:
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XP11 extrapolates flight model from a source model. It takes a source model in a certain format (be it 3D, values, both) and derives the model and behaviour from the source. You make the end result matching reality in fine tuning the source data (shape, values etc…).
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The more they refine their equations and physics, the better and closer to reality the flight model.
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The more they refine their technique, the better the flight model will match any flight situation and physics
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To illustrate what I’m thinking of with this: when they simulate air flow in inverted flight, the model will fly inverted as expected. Or when they simulate the air flow from the props hitting the tail or the elevator, you’ll get expected results from these as well. -
FS2020 bends the flight model from a target performance. It takes a target behaviour, and a base source model (FSX area type), and integrates the former to match the latter. Extra elements are therefore not building blocks of a refined model, they are a necessity to converge the solution from a few target data point to a few source model data point otherwise their wouldn’t be enough precision to integrating the target performance.
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The more they refine their equations and physics, the closer to target performance the flight model.
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Regardless of the refinement, it won’t make the flight model capable of matching flight situations which are not accounted for in the target performance model.
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To illustrate what I’m thinking of with this: if there are no inverted flight target values, it won’t fly properly inverted. If there is no provision for target values defining the prop wash effect, it won’t be simulated either
I believe therefore both XP11 and FS2020 models are doing the same in the end: matching a target value to a source model. Both are using a source model based on geometry of some sort, but the difference seems to be the target model. XP11 target is real physics and air flow, FS2020 model is expected values:
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The former is not constrained, the latter depends on the accuracy and number of expected values.
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The former could produce convincing and acceptable simulations for any flight situations but they could be wrong as a whole, the latter could depart outside its envelop in cases for which there is no matching target to source integration but could be right where it is well defined.
I wouldn’t pretend knowing which one is better than the other, but I can say at least the FS2020 documentation about XP11 is wrong because it doesn’t take in account the latest XP11 developments in the flight model since XP11. It looks in fact as-if the FS2020 SDK docs was redacted by the time they started developing FS2020 and this relates to XP10 area flight model docs (the FS2020 SDK docs about flight model could just be the internal memo they’ve redacted for MSFT when ‘selling’ their approach to the decision maker). And if I’m not mistaken, FS2020 approach is closer to what is used in the industry like in Level D simulators where the flight model is not accurate but is matching expected values for standard flight regimes and situations (it was fun once making barrel rolls in a 737-400 simulator 2 decades ago when all of a sudden the platform was going haywire when 180 deg inverted 
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In the end, I still find XP11 more organic and fluid in the various flight regimes and envelop, whereas I find FS2020 more predictable and synthetic in general.