I would give myself 3.5. I am a newbie, I listen to my elders and seek advice, and then - experiment. I can reach something close to perfection with teas I know, my standard blacks and most of my Japanese. I can also produce quite a mess with a new type of tea, as I have proven with my wuyi's. But I'd like to think I am trainable.
Wuyi Ensemble in the morning. Now finishing up the last of Sencha Fukamushi.
The new kyusu performs wonders - I swear my sencha's taste is deeper brewed in it. And while this may be subjective, here's an objective parameter. From the same sencha I could produce 3 steeps in my tetsubin with a brewing basket. The 3rd steep would be kind of weak, a good evening tea. The kyusu can make 4 steeps from the same amount of the same sencha, and the 4th steep is more flavorful than the 3rd from my tetsubin.
I now understand why people use specialized vessels, they make better teas.