Doctor Who is a show that's all about change, with new Doctors allowing the creative team to revamp the series and try something fresh, especially when a regeneration coincides with a new showrunner.
Some fans may not like what an era brings, but they only last few a years, and freshening things up is probably why the show has gone on for so long.
Current showrunner Chris Chibnall and Jodie Whittaker's tenure will be coming to an end in 2022, and now the BBC is promising that the next era will be a change of pace.

BBC
"As with any change of Doctor and showrunner, we'll be radical [...] Change is ahead," said the BBC's Director of Drama Piers Wenger at the Edinburgh TV Festival (via Elliot Gonzalez).
Whittaker and Chibnall will be leaving next year after the upcoming series and a handful of specials.
"I don't think I'll ever be able to express what this role has given me. I will carry the Doctor and the lessons I've learnt forever," the actress has said.
"I know change can be scary and none of us know what's out there. That's why we keep looking. Travel hopefully. The universe will surprise you. Constantly."

BBC
The upcoming series will see Whittaker's Doctor and Mandip Gill's Yaz joined by John Bishop's Dan, as the Doctor searches for answers following the revelations that were unveiled during the latest batch of episodes.
Whoever takes over from him, Chris Chibnall won't be involved in the decision-making, as he's admitted that picking whoever shepherds the show from here on out is "way above [his] grade".
Doctor Who airs on BBC One in the UK. Series 13 is due to premiere later this year.
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