Cutters themselves are good weapons, it's just they're not easy to use.

As it stands, the Dread Venom Striker is good and balanced. It hits fast, deals poison so it can hit harder, and is one of the only swords to deal poison damage.
However, the Wild Hunting Blade has a rather odd spot. While it sports a high damage bonus VS beasts, it still only deals normal damage. While this may be useful if a slime turret or lumber shows up in a wolver den, the weapon is very easily outclassed by the DVS, at least damage wise. The WHB has a fair flinch rate, but beasts flinch rather quickly as it stands. I would thus recommend converting the Wild Hunting Blade into a piercing variant, and removing the beast damage bonus. Piercing damage is effective against both fiends and beasts, both of which are countered by fast weapons. Design-wise, making WHB piercing damage is a no-brainer - it's colored yellow already!

I will say that cutters should be stuck with normal and piercing variants only. Elemental cutters would be okay, but most constructs/undead are slow moving as easily group up. I really can't think of a scenario where I'd prefer to bring an elemental cutter over brandish/DA/hammer. Similarly, shadow-weak enemies are a bit more dangerous to get close to in later tiers. Slimes with their lock-on tackle or 360 degree attacks, and gremlins with their rather brutal spin attack, knockback, or bombs littered on the ground. The cutters also have probably the shortest sword reach in the game, making engaging these enemies even more dangerous.

So cutters should remain normal/poison, and pure piercing damage. Now, how about spurs?

Spurs I feel could probably open up to shadow damage. Their charge attack should be changed, but not in the way you've suggested.
Instead of the spurs releasing a large single disk, they would release what is essentially a mixmaster bullet. At 4* they fire a projectile every sword swing, and at 5* they release 3 projectiles every swing that curve to all end in the same location. The charge bullet would fire 1 large mixmaster bullet at 3*, 2 crossing ones at 4*, at 3 spinning ones at 5*. 2* spur still retains current charge bullet.

This turns spur from gimmick weapon into fast chaos. When statuses are added into the mix, the sword would be devastating, and its quick swing speed means it isn't limited to being just another brandish which is spammed for its charge (especially if the charge attack dragged enemies back towards the user - this would be a bomber's best friend).

I can see this version of the spur being in shadow, piercing, and normal variants. Elemental is a possibility, but with the proposed changes to the cutter this would give every specialized damage type 3 different sword types (elemental: hammer/sealed/brandish, shadow: spur/sealed/brandish, pierce: flourish/spur/cutter), and at the same time, all of these sword types are genuinely effective VS the monster types they're up against.

What you guys fail to take into account is just how powerful specialized cutters would be able to become. If both hits were changed it would deal an additional 65 per hit or 130 per click- almost doubling its damage. At this point however I would love to see it- it's far riskier to use cutters than it is just about any other sword type, and swords deserve to be top dog when it comes to hacking and slashing up close and personal.

An elemental cutter would be terrible as it would either make rocket hammer redundant or be redundant itself, but a shadow cutter would be plausible, as it would create a high damage single target shadow weapon. Using it alongside maskeraith's deadly shadow cloak would very likely allow the player to kill a lichen colony, or more importantly gremlin mender, in one or two combos.

If we want to go a step further we can give it the brandish treatment. What's that you might ask? Take its damage values vs something w/ no damage additions. Now change its damage to split normal/whatever. Now make it to where it does the same amount of damage to the thing... so that it appears unchanged to the naked eye. What does this accomplish? It gets more benefits from damage up and is more capable vs. enemies that resist it. I did the math a while ago, and such a piercing cutter would be capable of some pretty serious damage- like crushing Vanaduke in a few combo.

Plus one for super cutters.