[Autumn]

I'm pretty against this wholeheartedly, sapping people's momentum by resisting something seems fair to me.  Lots of people already attack in ways you can't resist anyway. It sounds more like you have an issue with drowned woman more than anything, or an issue of it not being fun not being able to hit someone three or four times a turn with your fleur crits. . .Which is valid ,but like. . .If they specifically are building to stop you from getting to hit them three or four times that should bea thing they can do.  And its a lot easier to get huge critical percentages than it is to get huge critical resistance percentages.

Drowned woman was never an issue before holy got absolutely gutted. Just having her in your pocket caused you to eat fat holy damage multipliers, which was an actaully fair balance. Now holy sucks so having her is free, and all you get in return for her install is a dark weakness that's mitigated by having a carbuncle exist in your pocket.

I'm also just going to use this space to say that I think dark bards negating 15% of your resistances is insane, especially when sound already has basically no way whatsoever to be resisted outside of using a really shitty set or specifically being a heron.

TLDR: Make holy good again and make drowned woman an actual choice.
I think resists sapping momentum is fine.
Lots of dagger and fleur people use acid weapons and stuff anyway - if you're specifically building to be good against something then you should be good against it, and losing one momentum per attack really only messes up fleur crit people anyway, otherwise all it generally amounts to is not letting them guard or use a magic stone that turn.
Its also how you stop bosses from hitting you twice in pve, which would suck to lose.

There is exactly one physical damage weapon that does acid damage by default and its a shuriken, the vast majority of weapons have Pierce damage actually, and with build options such as a Canvas Gunfighter's Boots you'll find that resisting not only the more common damage type, but also the most effective as many daggers and bows are very scary is just an effective way to deny damage.

It also serves to make elemental damage weapons less appealing as a result of this, and if you want any arguments as to why this is a bad thing from a game health standpoint, we should look back to the many arguments about on-hit effects impeding basic attacks as a good way to gauge why an Electric Axe hitting lightning resist, despite hitting a critical hit, is incredibly toxic to melee weapons.

Sure, a bow that was already in range of you hitting a resist is actually not that impactful to your overall turn, but an axe build is forced to walk up into your face sometimes to do it's damage, thus their high critical rates bumps up their consistency and doesn't make them lose out on literally half of their damage cause they hit a resist they have quite literally no say over aside from splash. (which is specific to ONLY lightning resistances and certain classes)

Now, here's a list of the weapons and their different damage types I've counted, you can see which damage type is the most common among most weapons:

Martial Weapons + guns and bows:
93 Pierce
70 Slash
35 Blunt
3 Fire
2 Ice
1 Wind
1 Earth
3 Dark
2 Water
2 Light
3 Lightning
3 Sound
1 Acid

Tomes and Staves:
8 Fire
1 Hellfire
8 Ice
11 Wind
11 Earth
7 Water
9 Dark
9 Light
8 Lightning
2 Blunt
3 Slash
4 Sound
2 Acid