tl;dw
Seriously, if he has info on this specific issue point me at least to the video where it comes up, I’m not going to wade through a prolific youtuber’s account to try and find the videos that make your point.
I did watch some of it.
Namely this playlist: https://www.youtube.com/watch?v=VnkVlK3BFLw&list=PLMUtS78ZxryO9NKU_ceM-LhcnSnAc2kHV
(not all of it)
and this: https://www.youtube.com/watch?v=9qJBGlChcXU
Also, he is biased against katanas. If he is right or not, i dunno, but he is convincing.
summarizing on what he says:
Material:
Katana: Harder edge (brittler and sharper - high carbon steel + patternwelding to make it sturdy) but soft back (much less carbon here) to make the whole blade strong.
Longsword: Entire blade from the same good quality steel. Not as sharp as the katana edge (less carbon than the edge, but more than the rest of the katana), but much more durable as its all steel.
Blade:
Katana: Very rigid and thick blade. Usually quite a bit shorter than a longsword.
Longsword: The blade is flexible and has a slimmer profile.
Length:
Katanas usually shorter than longswords.
Balance and weight:
Katana: Due to blade thickness, amost as heavy as a (longer) longsword, and more blade heavy. Two handed grip.
Longsword: Again, two handed grip, maybe slightly heavier, much less blade heavy.
Speed:
Katana: Same length grip, shorter blade.
Longsword: Same length grip, longer blade. Slightly faster since the tip of the longer blade will be moving faster.
This of course is not taking into account styles and moves.
Thrusting:
Katana: Thrust very well due to sharpness and rigidity, but should find it hard to pierce steel armor. For flesh, just as good.
Longsword: Designed to thrust (the whole blade is wedge-like) and to pierce steel armor.
Cutting:
Katana: Cuts very well due to blade sharpness, makes cutting easier owning to blade rigidity.
Longsword: Certainly worse at cutting. Less sharp, blade more flexible so user needs more skill to cut well.
Handguard (won’t play much of a role in cata unless fencing against someone with a melee weapon)
Katana: Quite small. No big hand protection.
Longsword: Larger crossguard.
PS. This is quite a bit of a derail.
PS2. I got to say i learned a bit from all of this 
PS3. I did not watch the part about general weapon parrying, but here it is: https://www.youtube.com/watch?v=ZeDFc2QQ-XU&list=PLMUtS78ZxryNzppeniLfdHb_ftc7huhEY
A playlist is no better, I’ll read quite a lot of good reference material, but my tolerance for watching video is very low, it takes too long.
From your summary there are no changes to make.
‘blade tip speed’ isn’t a good reference for our ‘weapon speed’, which is how long it takes to attack and recover from an attack.
I did not post this to force change, only to make it known. Hell, it contradicts my earlier post on a few points.
I can agree that the current implementation is mostly fine. (not true! where are the thrusting attacks for all swords??)
Durability, stats etc. seem correct though. I cannot comment on weapon styles as the videos provided no info on those.
About speed… you know, its a function of the user and the weapon weight/balance/length. How fast can one man attack with a stick? A heavy stick? A top heavy one? Its a derivative of the weapon’s properties and we know them more or less.
Anyway, i am certainly not a swordfighter so i can’t come up with a correct algorithm on speed. Though the current speeds seem fine as they are.