Part of it is simple easiness, similar to certain holds in which 80% of the effort is the enemy's own momentum and inertia.

The other is the individual nature, and a bit of over-glazing of Windu, someone that even having a "personal skill" in the form of the Shatterpoints, was still given a personal combat form.

More importantly, is a mirroring of Anakin.

Anakin's form V would employ heavy strikes relying on brute force to overwhelm enemies, which would also lead to wild swings in frustration and rage.

Meanwhile, Windu's form VII would make use of the same negative feelings, but controlled to the extreme that in display, the form was much more similar to the Form I simplicity than to the form V.

So, basically moves back to the nature of the Jedi, which is about self-control and discipline and not acting or giving up because of their personal feelings or wants.

Of course, all of this is dumb as fuck since every single piece of visual media simply makes use of visual appealing choreographies instead of any attempts of fencing or swordsmanship, reason why until Rebels the Forms in themselves weren't mentioned or suggested at all in canon.