One of the main flaws of the season premiere was heavy use of the Idiot Ball. Why didn't Tom just show Chloe his magic instead of merely insisting she couldn't go on TV? Why is a TV special considered ultimate proof of magic, instead of something most people will say "oh, special effects?"
Likewise, the secondary characters fail to develop. Chloe may be realistic, in that she welcomes fame as most teenagers do, but she has few traits beyond that. In contrast, a similar character in the SJA episode "The Madwoman in the Attic" has a friendship with one of the protagonists before the story opens and with another character during the story itself.
Finally, any characters taken by the Necross are prematurely aged and never mentioned again. It would be really neat to see one of them again and learn more about how it affected them. I mean, are they now biologically 50, 60? It feels really callous to just leave them. My vote would be for Mark from the series premiere, since he's played by Elisabeth Sladen's husband, but I'd be fine with Chloe or anyone else.