A show that does a simple, focused thing competently and enjoyably is rare enough, and in that sense there's no wrong in calling this show a classic and a treasure.
Some of the details may have been lost in translation, but, overall, the parody managed to pull together two distinct TV series and keep their tone while adding to the work.
These specials not only were there to give Tennant the send-off he so rightly deserved, but also to help the series runners manage the transition to a new head-writer, as well as casting a new Doctor.