The apparent rules for "previous experience" seem to be as follows:
a) You can be a pop singer and have faffed about on stage a bit to your own songs as that isn't regarded as serious experience but the sort of stuff most persons with half a sense of rhythm could do.
b) You can have gone to stage school as long as you haven't used the singy/dancy bit seriously in your career (pop singy stuff doesn't really count - see above).
c) Acting isn't regarded as relevant experience - it just means you might be more comfortable performing which is forgiveable.
d) Having said all that, any perceived relevant
dance experience (i.e. a or b) isn't an advantage in terms of the public.
(*Turns into Lloyd Grossman*)
Look at the evidence:
S1 - Only person with anything like relevant experience was Claire Sweeney. She was a shock boot.
S2 - An exception explained by the fact that Jill's experience wasn't widely known
at the time (I remember it being played down as "ballet lessons as a child" in an article I read) and she had far less competition.
S3 - Zoe Ball was the only vaguely relevant celeb and she finished a distant third despite having scored more highly than anyone else all series.
S4 - Emma Bunton was widely disparaged. Perceived teachers' pet and never very popular.
S5 - Another exception. Alesha fell into category a) above but she got away with it partly because Kelly, Gabby and to a lesser extent Penny took most of the early flak and also possibly because of the way the series fell in terms of dances and dance offs. She may have won anyway but I remember an ITT after her dance off week where she plaintively squeaked, "I've had a journey too." She was still vulnerable and she knew it.
S6 - Despite being possibly the best technician Strictly's had, Rachel was generally as popular as the clap (although still more popular than Lisa). Dragged to the final two through sheer judgepower, she stood no chance against Tom Chambers. I liked her though.
S7 - No obviously relevant celeb. Ali, Zoe, Ricky and the like may have gone to stage school and obviously were from the acting profession but that wasn't really the reason that prevented them from winning.
S8 - I didn't know Kara had gone to stage school. And if I didn't know others may not have done either. Even if they did, she'd never been known for anything other than straight acting (see c) above).
S9 - Jason was the only one with real relevant experience and we all know what happened to him. (Of course it didn't help that he'd learnt "Conversational Charisma" at the Gary Barlow School but still).
S10 - Kimberley is an Emma B or an Alesha. She's not being as harshly treated as Emma because she's not out in front like Emma was and because, like Alesha, she has others (namely Denise) in the way to detract. Having said that, she's probably not getting away with her experience; Saturday's vote is possibly some indication of that.
And so we come to Denise. Well, never in the past has a contestant come to SCD quite so obviously experienced. Everyone who knew who she was expected her to be very, very good from the outset. And apart from a slightly dodgy waltz, she was. And still is. Look at the way others with less obvious experience have suffered with popularity over the years and then realise that Denise's last major "role" was on a series of reality shows judging others' suitability for West End singing and dancing parts and understand why her experience is regarded more suspiciously than the rest.
Or don't.
I don't really care

.
I'm so sorry, I appear to have written the Domesday Book.