Have you actually tested this?
i played this game a lot. never auto calc as i live for field battles and i charge in there fighting everyone. i've killed thousands using my long glaive and from those kills i have extensive experience and observations
fighting people with shorter weapons is vastly easier than those with longer weapons.
surprisingly i have the most trouble when i'm fighting the eleftheroi minor clan who are almost exclusive cavalry with 2h lances like the imperials. despite having almost no armor, their reach are able to hit me outside my range and i take a lot more damage on average compared to fighting even banner knights
i'd say against lancers with 180-200 reach weapons I'm able to deliver 10-15 hits before taking 1. but against the 240 reach weapons i'm taking a hit every 5 attacks i land and that's using a 206 reach weapon. i can't imagine if i had a 140 glaive, i'd probably get wrekt.
once again, the glaives are superior in tight spots, clusters. dog piles, which are situations you never want your cavalry units in. but they can't come close to the spear in a charge. you need to have your cav line very long end to end, but not deep, 2 lines is enough, 4 is too many, this gives them good coverage of enemy ranks. the opposite would be a column and you'll get wrekt if you charge like that.
it is much easier AI to connect with a sweeping strike.
not just for the AI, for the player too, not just in the game, in real life too. a swing has a "hitbox" that's a line, a diagonal line at that. whereas a thrust has a "hitbox" of a point. much much easier to miss and block. AI aiming problem needs to be address, i've mentioned it earlier, all cavalry AI only aim at the ground level, so when they attack another cavalry they end up hitting the horse, and if they are using a 2h pole they might swing and hit the riders leg. that's another advantage with the glaive