Okay guys. If you haven't played the game before, and this is your first time playing it, I've got an important hint that should make blade mode a lot easier to use: go to the options, and change the control scheme to control scheme B.
Let me explain why:
The default control scheme uses the left analog stick as the camera control and the right stick as the stick you use to orient your slashes.
Example:
Here, using the default configuration, tilting the left stick will move the view around, whereas tilting the right stick will make the blue line you can see on the screen rotate. This blue line tells you where you're going to make a cut.
Now, in the game there are two ways to slash things to pieces: either you flick the right stick, or you orient your slash using the right stick and then press one of the attack buttons (X or Y) to make the slash. The second method is more precise, as you don't risk changing the orientation of the slash as you flick the stick. However, you can see that we have a problem here: you need to orient your slash using the right stick, and then press one of the buttons directly above it without releasing it... It just won't work unless you're using the claw.
So we come back to my recommendation: use control scheme B, which inverts the two sticks during blade mode (the control scheme doesn't change anything else). That way, you orient your slashes with the left stick and cut using X/Y. No problem there. Orienting the camera also feels more natural since it stays on the right stick (which is the stick used during normal gameplay to move the camera around).
The thing that really motivates me to post this is that lots of people complained about two of the latter bosses in the game, saying that blade mode wasn't precise and stuff like that, even though it absolutely is if you use it the right way.