As an experienced Claw user, I can attest to that. They have very short range and on average quite slow attacks, which is why it’s highly necessary to use the leaping slash and double-hit effectively. The leaping slash closes the distance and combos excellently when followed up by a double-hit, while the double-hit itself has a very short start-up time compared to the single hit, which means it should be your primary attack. Consecutive double-hits also have very consistent timing, which a) makes them easy to parry and b) makes it highly unlikely an enemy is going to poise through that onslaught. By the time they regain their poise, you can probably get three hits in while they’re starting to swing, at which point they’ll be staggered again. Not to mention the bleed that will inevitably trigger.
Double-hitting is also effective after rolling or running. The Claw’s rolling single attack seems bugged because after rolling, your character performs another half-roll (the latter half) and stabs with the Claw. It’s very unwieldy, which is why I almost always double-hit.
The Claw has a lot of advantages but it’s definitely less versatile than the average katana, and as my Hollow character I often switched to a katana from the Brigand Twindaggers, which have similar drawbacks. Now that I have fully upgraded and Hollow infused Claws, however, I’m not switching them for anything.
In other news, I found a spot in the Catacombs of Carthus where you can go out of bounds. It serves as an excellent hiding spot for when I’m baiting invaders; I curl up there with the Dried Finger active and wait for the invaders and Blue Sentinels to arrive so they can duke it out. I also got someone summoned who casts Hidden Body as a white phantom, making them appear almost exactly like a player’s spectral echo that you constantly see running around the levels. Consequently, invaders sometimes completely fail to notice them.
Ah, I forgot to try putting messages down there! Will try that now.
Edit: It’s possible! Whether other people can see them is another question. But more importantly, I dropped down onto an invisible ledge (difficult) which let me drop down on the top of the tunnel leading to the pit under the bridge (also difficult) and from there it’s just a short drop into the water. Completely pointless, but fun!