It was a bit sentimental, but I don't think excessively so.
All too often the only thing the Doctor uses his time machine for, is to get to some random location where the storyline plays out. Today, just for once, he actually used it to do something interesting. Taking an artist who wasn't appreciated in his own era to see that he's considered one of the greatest painters of all time (up to now anyway) is the sort of thing you would want to do with a time machine.
Not a bad episode, although it seemed a bit contrived with the storyline about the beasty not really being very interesting or important, and a lot more about how Van Gogh was treated, behaved and felt.
Next week we get James Cordern playing himself.
Doesn't James Cordern always play himself?