Adding vinegar necessary?
 

I did a search and can't find a definitive answer.

When transferring your SCOBY to a new batch, do you have to add vinegar? I have shied away from it for no reason other than it seems like "cheating" to me. I do add some of the previous batch of KT as a starter, and it seems like that ought to be enough.

Is this a personal taste thing, or an important aspect?

From all i have read you only need to use vinegar the first time when you have no Kombucha from the last batch to transfer so it sounds like your doing it exactly right.