The design of the T28 is such that it has a long tail movement. It is much like a pattern plane and does not require a huge amount of elevator to be effective. I would go back, put the recommended throws in the model, add a little expo to the high rates, recheck the CG, and make sure nothing is loose inside like a battery pack or something that could have moved during the taxi. This time don't let the TP just gun it and take off, ease nto the throttle and let the plane reach take off speed and then ease into the elevator. There is no need to snatch one off the ground on a test flight (not that he did, but am speaking from experience).
The T28 is a good design and generally when balanced correctly they fly very weel, but you don't need alot of elevator or rudder throw in these models.