Doctor Who is a difficult one to gauge.
On those weekly ratings alone - which, in fairness, is how we generally discuss the success of most shows - I’m erring on the side of it being slightly disappointing.
However, the BBC came in for quite a bit of flak for the midnight iPlayer release, which seems to have been largely dictated by the American Disney+ schedule. A simultaneous release sees it premiere at 7pm on Fridays there. I think most people would concur is a far more lucrative slot, even in an on-demand world, than being dumped onto iPlayer at midnight. The BBC will naturally defend that decision, but when they’re particular over EastEnders, for example, premiering at 6am, I don’t believe they’d have Doctor Who on iPlayer at midnight if they could help it.
Ultimately, it’s still an important show for the BBC. That I don’t think has changed. And I’m pleased it has a Saturday broadcast slot back (though putting two episodes in a support slot before Eurovision made them very missable, I’d say). However, this series feels short enough (eight episodes) that I feel they may bank on it being something audiences choose to binge-watch as a complete story arc once the whole lot is released. It'll, thus, be interesting to see how the 28-day figures look.
I suppose more than anything else, though, in the same way as EastEnders needed to be good for almost two years before the audience eventually recovered, Doctor Who is probably in a similar situation. Even though it's a very different show, it's been back on-air for almost 20 years now and has been perceived as being in the (creative) doldrums for long enough that it's going to take more than a new lead and a new/returning showrunner to turn things around.