I dont like it. I guess its a good thing in disguise. There were many unusual "pop hits" this year that there was a little bit of everything. It wasnt Dr. Luke'd driven which shows that music is at least progressing.
i think he's using a different list of songs, that's why WFL, SAIKI and TTWE made last year's mashup. he's doing it differently. the definite hits will make it in, but a few of those songs in the top 25 underperformed overall and might not make it in.
Virigin Radio in Canada had an advanced listen, it's apparently his shortest USOP mashup and there are mixed reviews, mostly negative but the reviews have been negative since 2010 and they've sounded fine so far (imo), i believe it when i hear it.