Looking back through the years, it's not often that the "best" dancer has won Strictly.
2021 Rose - astonishing to dance to that level as a deaf woman, but she was arguably not as technically good or versatile (too many wafty/floaty numbers) a dancer as AJ - who I know had to pull out of the final, but I doubt she'd have beaten Rose even if she had competed. She captured everyone's hearts, is a genuinely lovely person, had a moving partnership with Gio, and so was the nailed on winner.
2020 - Bill Bailey - certainly not the best dancer, that was Maisie. He's a brilliant and well loved comedian and surprised everyone that an older bloke could dance that well. Had a charming partnership with Oti the goddess.
2019 - Kelvin Fletcher - fabulous to watch, had fab chemistry with Oti, but Karim was the better dancer that year. Kelvin pretty much bagged it from the off though, with the lore around him being the last minute replacement given 2 weeks' notice, having the work ethic that went with that, and dancing a fabulous Samba on week 1 that garnered memorable comments from the judges.
2018 - Stacey Dooley - arguably Faye Tozer was better that year. Stacey is a down to earth and very likeable girl next door made good, and it was Kevin's "turn".
2017 - Joe McFadden - I would say Alexandra Burke was the stand out dancer that season, with Debbie McGee putting in some fantastic performances. A close year.
2016 - Ore Oduba - surprise winner over Danny Mac, although I think Ore was a better dancer than given credit for. Not sure what swung it for him over Danny (I'd never heard of either of them before Strictly), but he did nail his final dances and did one of the more memorable show dances.
2015 - Jay McGuiness - Did one incredible Jive. I don't think he was stand out that year otherwise, and Georgia May Foote was arguably the better dancer. However, that Jive and his shy personality endeared him to the audience and he never looked like he would lose.
2014 - Caroline Flack - yes, fair enough she did stand out above Simon Webbe and Frankie Bridge.
2013 - Abbey Clancy - great partnership with Aliaz - terrifically entertaining, beautiful and surprisingly endearing (and Abbey wasn't bad either) . But Natalie Gumede was the more accomplished dancer.
2012 - Louis Smith - Came in as an Olympic hero, with a near miss of a gold story. Struggled week on week to show his personality and retrain his gymnast's body to loosen up. Came off his ADHD meds, nailed a charming Charleston and found his way to the final. In the final, did a groundbreaking Show Dance and much improved Dirty Dancing Salsa. But overall, Denise Van Outen was the strongest dancer all season and had a strong final. She was stuck with the annoying James Jordan and viewed as a ringer.
2011 - Harry Judd - I didn't watch this series, so not sure whether he was the strongest dancer or not.
2010 - Kara Tointon - as above.
2009 - Chris Hollins - I didn't watch, but I'll have a guess that he won the dad dancing popularity glitter ball, rather than the best dancer one.
2008 - Tom Chambers - charming man, but less accomplished than Lisa Snowden and Rachel Stevens and came bottom of the leader board in the final.
2007 - Alesha Dixon - from what I remember, probably the strongest dancer that year.
2006 - Mark Ramprakash - Hot Hot Hot partnership with the wonderful Karen Hardy. They were the best.
2005 - Darren Gough - self described Fat Lad From Barnsley. Winner based on best dancer over popularity should have been Zoe Ball or Colin Jackson (but he and Erin screwed up with unnecessary, and frankly a bit macabre, puppet dancers).
2004 Winter- Jill Halfpenny - no arguments having seen her Jive, but can't remember who else was in it.
2004 Summer - Natasha Kaplinsky - didn't watch.
My conclusion: popularity has pretty much always been the paramount criteria for the voting public. Ability to put on an entertaining and fairly high standard dance a big bonus. Being endearing in a national treasure sort of way, being surprising in showing dance ability because of age/weight/disability/past career path, or just having a certain something that captures the public's hearts will always win over technically accurate but otherwise annoying/grating/over ambitious/over-reliant on sob story/obvious ringer/doing the circuit of talent or reality shows/never heard of them and couldn't care less about their back story or where they go from here type competitors.