Doctor Who Social Club

I don't think that was necessarily an insurmountable problem, and TBH I think RTD made it worse with some of the decisions he made. Getting David Tennant and Catherine Tate back is fine, but why lean so heavily into continuing a plotline from ~15 years ago if it's also for new people? Or tell it from Donna's perspective: she's leading a normal life, mysterious time traveler shows up, she learns about him alongside the audience like it's brand-new, then throw in the twist that she knew him before and got her memory wiped. That way new audiences can follow it without feeling overwhelmed, and long-time watchers can have fun with all the little hints you drop along the way.

And why introduce a concept like bigeneration if it's for a new audience? That even confused a lot of long-time watchers from what I saw, and there was really no need for it, just to create yet another David Tennant that's out there somewhere who we never hear from again. Plus I thought it was really weird to give him his own TARDIS, because then for the whole rest of the series I was just thinking about it. I know the David Tennant one is supposed to be retired and healing, but then you have a literal god of death show up and start ending the world, and that other Doctor with a TARDIS doesn't get involved at all? Not very Doctor-y IMO. But yeah, if you're introducing new viewers to core concepts of the show like regeneration, don't make it a weird one.

And then aside from the specials the launch of the main series with Ncuti was weird too IMO. The Church on Ruby Road wasn't a strong start, then there was like a 5 month gap, and the they came out of the gate with Space Babies which I genuinely think is one of the worst episodes ever made and I'm convinced it killed any momentum the new series might have had right from the start. Anecdotally, my SO had watched all of New Who with me starting from Eccleston, no complaints even through the Chibnall era, and when it came to Space Babies they were like, "Yeah I think I'm out." The only reason they carried on watching was because they're a big Drag Race fan and Jinx Monsoon was in the next episode, but I imagine a lot of people bailed at Space Babies.

And for some reason I can't quite fathom, the whole RTD2 era seemed to be trying to both restart the show for for new viewers (including resetting it back to 'Series 1' and the refusal to include any of the regular staples of the show - the sonic that wasn't a sonic, no Daleks, no Cybermen, no Master etc.) but also seemed to be obsessively trying to cram in as many ancient nerdy lore concepts as possible - we had the return of a Doctor & companion from 15 years ago, the Meep, the Toymaker, Mel, a sequel to "Midnight" 17 years later, the Rani, Sutekh, Omega and Susan all within two (shortened) seasons and three specials. That I think is one of the main decisions that derailed it from the start - you can either clean-slate it and get right back to basics, or you can make it a celebration of 60 years of the show for the old-heads, but you can't really do both at the same time and expect everyone to be on board.