in my impressions i dont mind the left click swing/stance mechanic. no idea what right mouse button does at all... i do think some tweaking is needed. for example. it feels like stock warband instead of crpg. the weapon variety is non existant (no pike) but more importantly, it seems all swings in all stances seem to have the same speed, where i remembered crpg had different swing speeds on all 4 directions.
For 2h right button does parry - you have to be out of stance, time it right and choose right direction.
They probably decided to add all weapons first and only then start balancing - good idea imo.
If you would had a chance to play the bot version, like many of us did and set difficulty to Insane, you would notice that the bot always chose a faster swing than you.
This is just my observation so it might be wrong, but:
Upward strikes were by far the fastest swings, but they didn't have much reach and it was a bit difficult to land them accurately.
Side swings were easy to land and had good reach, but were generally a bit slower.
Side-downstrikes were a bit faster than side swings, but a bit slower than upward strikes - they were a balance between reach, speed and trajectory, i.e. how hard to hit
Overheads were definetely the slowest and a bit ard to land, but had superior reach imo
And finally stabs - long reach, super fast, but very easy to miss the enemy