On a personal level, I'm sorry for Hayley in that she was probably a little unfortunate in the last series to get a fairly quiet celeb as a partner, and since she was on the quiet side the partnership didn't quite spark. If she'd had John Sergeant as a partner it might have been a different story. Other pros (e.g. Matthew Cutler) haven't had very auspicious starts but have then established themselves. I think also, given that the majority of the pros have been asked back, it would have been polite of the BBC to have phoned, rather than emailed and explained the reasons, even though I accept that this was not a sacking, but simply a decision to not renew her contract.
However, in practical terms, I guess that's the way showbiz works, in that people have to grab their opportunities when they're given them, and if they do manage to get a second chance, then they will count themselves lucky. Also, from a viewer's point of view, given that she didn't really establish herself, I don't think this is going to make a lot of difference to the show itself.