You seems to forget that France inspired its centralization from English one. Philips Augustus reforms were copy paste from Henry II Plantagenet... England was the most centralized kingdom in the middle age... France become such gradually and later.
This is true, but two things must be considered:
The first is that the reason British centralisation directly influenced (and even caused) French centralisation is... well, the way OTL went. British involvement in France led to that reaction, and is in fact an illustration of the cause-and-effect whereby one centralised country can threaten a less centralised one, and thus force that other one to centralise or be subjugated. This is also why the initial POD suggested would be too late to prevent this. But an earlier POD (if it's the right POD) can easily change this. British centralisation did not directly affect many other contental countries, and they did not centralise because Britain did. They hardly cared or took note.
The second thing hooks into that. It's the fact that a centralised Britain that doesn't actually threaten any powerful-but-decentralised European country will be far less likely to inspire centralisation there. France was a direct threat, often right next door, with a formidable land army. Simply put: centralising France terrified her neigbours, and gave them no choice but to centralise themselves... or be conquered. Britain, across the water, is (at least as far as perception goes) a less direct threat. If you get the right POD, you can make it so that French centralisation doesn't occur as in OTL, and Britain is not perceived as a threat by the various continental powers.
It was never said here that just
any POD will sort that effect, but I am confident that it could be done, and would have the effects that
@John Fredrick Parker is looking for.
There was a strong, structural and multisecular trend towards centralization that started in the 11th century with a strong movement of demographic and economic growth, with urbanization and development of trade.
England of France were the first that loved on the path of centralization and did It further than any other european kingdom but there was such a trend in all Europe.
This happened with the spanish kingdoms whose number diminished in the 11th and 12th centuries.
This happened in Bohemia, Hungary, Sweden, Sicily-Napoli, in Poland, ... Etc.
The German and north italian parts that were the main parts of the HRE (I know Bohemia was part of it) are the exceptions that confirmed the rule. This exception is what I previously called (in other threads of this forum) "the plague of empire". The structure and fabric of the HRE was based on selling by pieces the foundations and resources of power to the lesser levels. It met the same fate as the Carolingian empire and It was doomed to do so.
This view is a little too determinitic for my tastes. Depending on how one approaches history in general, one might indeed believe that the trend is the dominant factor, and that there are simply early and later examples. Personally, I tend more towards cause and effect: the 'early examples'
cause the later examples.
In reality, both things are of course true to some extent. Demographic and economic growth, urbanisation and the development of trade certainly had their political ramifications, and would still have them in an ATL. But I do believe that you give too much weight to these developments as being the big and mostly inevitable cause of political centralisation. I maintain that England was considerably more centralised than all others (and that this was for a large part a result of the Norman conquest), and that the English interference in France caused France to also become more centralised as a direct result. And, of course, that the far more direct continental threat of centralising France led to centralisation among various rivals of France.
If this whole domino effect had been halted at the outset, the general trends of demographic and economic growth, urbanisation and the development of trade would (I think) have resulted in some modest (and more local) centralisations of various forms of political authority -- but not in the centralisation tendency of OTL. ecause, yes, there was some consolidation of the Spanish polities, certainly... but that development then halted, and only got back on track again when centralising France became the big bad rival next door. Some local Italian unification took place, but I don't see any serious options for a unified Italy before the Napoleonic (= French) disturbance forever shook thing up there...
Needless to say, this is
my reading of historical effect. I think the direct causality of geopolitical powers threatening each other for several enturies as it happened in OTL, had more effect in this whole centralising development than more general demographic and economic effects in the 11th century. Which is why I believe that preventing this causal domino effect with an early POD would mostly (but indeed not
entirely) cancel the whole centralising tendency within Europe. Someone who fundamentally disagrees with my approach to historical effect, and believes that socio-economic 'background drives' are far more important than I portray them (and/or that geopolitical pressures are
less important) will obviously see this very differently.
In any case, I
do agree that various economic, demographic, social, cultural etc. effects would of course lead to obvious political results (i.e. the formation of nation-states and bureaucratic government would occur and supplant feudalism), but I suspect that it would happen to a Europe consisting of many more, smaller nation-states. no Germany. No France. No Italy. Instead the nation states of Prussia, Bavaria, Saxony, Savoy, Tuscany, Sicily, Champagne, Bourgogne etc. (and if nationalism becomes associated with more local identities, ultimately no Austria-Hungary or Spain, either. So many ethnostates replacing the Austrian Habsburg monarchy as per OTL, and independent Aragon and Castille, etc.)
Basically, if
@John Fredrick Parker wants to prevent the end of feudalism, I don't think any POD in this vicinity is going to cut it. But if he wants to end up with a far less centralised Europe consisting of far more (and generally smaller) nation-states... I think he's looking for his POD in exactly the right place.