Before I ask my counterquestion I'd like to state that my time as cavalry was long ago, and it wasn't a long period, so I understand little of the mechanics.
But doesn't the slower speed mean that the animation is played lower, which means it is plyed for a longer time? Wouldn't that mean that with the slow animation the tip of the lance will remain for a longer time at the maximum possible distance to the player when stabbing? Wouldn't that go against your statement?
Because with a fast lance the time window for maximum reach would be much smaller, and thus it would be more difficult to find the right moment, wouldn't it? On the other hand faster lances have the advantage of being at maximum reach much faster, which means you have better chances in surprising moment, if you have no diffiulties finding the right moment to stab with max reach of course.
You know what I mean?
I understand your point but what I'd like to say is that we have to divide different kinds of lance's speeds into their usefullness groups.
For example Heavy lance requires very early releasing to hit the target in proper part of animation. It is hard because in the mid time the enemy, if mounted, can accelerate or slow down or, if dismounted, can move to the sides, jump, move in all directions basically. So it's hard to estimate the timing properly. It has a good thing that over the time that animation lasts, you can hit somebody and deal some damage, because attacking animation is long, though you won't deal max damage which is very significant as heavy lance has shit damage and you need total max of it.
On the other hand, lance can be released later and requires less predicting, but still works over some distance in which you can hit an enemy.
Last but not least, if the weapon was too fast it would be really hard to hit as it would be requiring very good timing as your attackwindow (that would allow you to deal damage) would be very short. This means that you would have to release your weapon in the very moment of the enemy being in the way of the lance, in it's reach.
PS. There is also this moment when you are at max reach and your weapon isn't moving any further. Usually when you hit an enemy at that stage you may deliver very small damage or just glance.
Proper timing is hitting an enemy just before the moment when weapon is at it's max reach - it's maximum useful reach
TL;DR
lance 2 slow - animation reaches useful maximum usually too late, prone to enemies who are changing position.
lance just as lance - timing easier to perform and can forgive a small change of placement of the enemy.
lance 2 fast - animation reaches max superquickly, but it's hard to attack not too early or too late. Have to attack in the very good moment. If enemy moves or not doesn't really change anything.
EDIT: I spoilered my wall of text.
EDIT2: Basically there are 3 important factors when it comes to lances: speed, length and damage. Length can't be discussed without taking speed into account. Speed also influents timing and timing influents damage delivered to the enemy. That's why speed of the lance is an important factor.
WomenPeople used to be like length is everything. Now length, damage and speed are all 3 that decide what weapon is good weapon. Heavy lance lacks one of those two new features, either speed or damage.