This pops-up fairly regularly and usually demonstrates that there are two camps.
My opinion is that a touch and go is a useful training exercise that saves the student a considerable amount of time and money and only takes a very short time to learn, therefore it's appropriate to use and teach it. In the general case power should be increased first because doing otherwise results in being lower over the houses than necessary; it is also the same sequence used for a go-around so things are more consistent for the stude. If operating from a long runway the sequence is less critical but I believe it's still good to use the same sequence as for a go-around, unless coming to a full stop (in which case it's not really a T&G).
The nay sayers will now talk about distraction during the acceleration, but others will point-out that training aircraft will become airborne and climb with landing flap, and also that the record does not show it to be a risk. The nay sayers will also usually be operating from long runways whereas those that teach power first will operate from less than 800m.
HFD