Okay, let's compare it to Dark Souls.
Dark Souls does not have directional twitch based blocking. To block all you need is a shield, to be holding the block button, be facing in the right direction. That sounds like good game design.
You can also parry. Parrying is 100% timing based. There is no directionality to it. Your character literally doesn't even have to be facing the enemy.
...Why are we comparing it to Dark Souls? Dark Souls doesn't use this mechanic. Why do people keep bringing it up? Because it's hard? I've beaten every boss in every dark souls games. With shields, without shields, parrying, roll dodging only. Why? Because it's fun. Am I tempted to use manual blocking in Bannerlord? Nope. Because it's not fun. Not even vaguely.
The most comparable game I have played was Kingdom Come: Deliverance; the combat system was one of the major complaints about that game.
Kingdom Come quite clearly used the manual block option from M&B as its inspiration. But judging from this threat, the dozens other like it, and the fact that they've already said that they're putting the toggle back into the game because of the volume of requests, it is not something that people widely like. At all.