I think there is a distinction between attack reset from an attack and the reset from a block. From a block, the reset is too slow and from an attack it is too fast. This is the most pressing issue with 1vX being unwinnable, even more-so than the less precise movement making out-maneuvering opponents extremely difficult without kiting and the huge swing arcs making precise return-attacks as the 1 against X extremely hard. Right now, when you attack and are blocked you can immediately enter into another attack with almost no delay, meaning that 2 people attacking 1 can spam attacks ad infinitum with no way to interrupt them.
In Warband, if as the 1 you double-blocked then you would have the initiative, because the attack reset from an attack into another attack was slow enough that the 2 attackers would not be able to spam attacks forever. This is provided that the 1 manages to force the two incoming attacks to connect at a relatively similar time (though it did not have to be precise) and is quick with their return attack.
In Bannerlord, if you double-block two incoming attacks, even at the same time, you cannot reclaim the initiative because the reset from a block into an attack is too slow, while the attackers enjoy an almost instant reset into their next attack.
Perhaps reset is the wrong word; it's more like there is a delay between going from a block to an attack but no delay doing one attack after another, particularly an attack from the same direction. This means that even with perfect 1vX blocking there is almost no way to reclaim the initiative, or any interludes in which to return attacks. This combined with the imprecise swing arcs and movement makes a 1v2 as a good player against much weaker players almost unwinnable, provided they know the basic mechanics, without horrendous and disdainful kiting, which in itself is only viable until the opposing players catch up.