I would rather see England knowing some sort of Davidian Revolution equivalent, making its institutions not less feudal per se, but a particular feudality based on similar basic principles but with an important substrate.
Harold Godwinsson, for exemple, had an important part of his legitimacy backed by his experience on Northern France.
Unless England going totally isolationist out of nowhere, institutional influence is bound to happen, as Carolingian Empire iinfluenced on England, or the links between Ottonian HRE and late AS England (trough cultural and diplomatical exchanges), without forgetting, of course, similar inner tendencies in England and post-Carolingian Europe.
I gave my definition of bacwards in the post you mention. It's not about being progressive or reactionnary. It's about how advenced in a specific tendency it was.
I don't think you can call germanic kingship "democratic", or even meritocratic.
When german peoples entered in Romania, they adopted relativly different usages, such as leaders being more warlike than traditional germanic priestly kingship.
The advencement due to arms took another importance as well there.
As to calling it an advencement or a regression...The unexistance of inherited entities and geographically stable (meaning, entities whom borders aren't too vague and actually acknowledged) was a factor of more general instability.
As territories and holdings were clearly identified , say in XI France, you still had many wars between king and vassals, but no real attempt to overthrow the king (mainly because this geopolitical division was granted by his sovereignty, and doing that would challenge the revoltees own legitimacy).
I don't point any moral superiority there, critically when the establishment of this system was made through a really difficult era during Late Carolingians, just that it seems it prevented some of the troubles that late AS England knew (huge revolts, foreign invasions) as the more "blurred" definition of institutions gave more room for ambitions.
Not that England needed any kind of push up to go in the general direction, it was already happening : while clear holdings and title inheritences weren't the rule, Harold did inherited his position from his father, for exemple.
Not only politically but institutionally, but apart from that it's exactly what I'm saying.
Scandinavians invasions critically, but also late unification, provoked the maintain of more...well, is "antiquated" more clear?. As in the maintain of an important slavery (that virtually disappeared in non-mediterranean regions at the XIth).
This text focuses on the qualification of tenures, institutions and military organisation in Saxon England and its comparison with feudality (Norman, Frankish, but also Ottonian), I hope you'll find it interesting.
Either with more able Late Anglo-Saxon against Scandinavians in the XIth, that would have made these changes maybe happening and achieving earlier, or with a 1066 PoD (that is as good as any, critically in the "later PoD possible" challenge), you'd have something along these lines.
But while it would probably go apar with Franks or Germans, going against already established and stable entities would be difficult (critically giving the
realtivly less avaible ressources and far less important population (1 million, at best), I tend to think that AS efforts would be made against Wales, Scotland and possibly Ireland while a more interventionist mood in North Sea is likely as well.