people forget that you are holding a 2h sword by the handle, making it way more unwieldy to stab, unlike polearms, which were in most cases designed to do so.
Especially the lolswords, try holding a 2 meter iron bar at the very end and stab with it. You won't be able to put much force behind it, and you'd be thrown off balance if used in a real fight, where such a long, weak and slowmotion stab would be easy predictable and parried. If anything at all with 2h stab, imho, it should be nerfed. (a slight nerf, probably another animation)
Maybe all oversized 2h swords(German lol greatsword, Danish lol greatsword, actually, all 2h swords with a stab animation from the "2 handed sword" and up execpt for the katana, since it's very short and light compared to the lolsword category) ashould have the polearm stab animation, it makes way more sense, and you would be able to stab stronger.
BUT, since we're talking about IG here, and not IRL, my post may be total off-topic, but these are just my 2 cents (hah, before the IG/IRL off-topic posts)