David Tennant should regenerate into the new doctor after Jodie.

Well he is about to do a new lot of Big Finish Audio's that will come out after the Ninth Doctor Christopher Eccleston's ones called The Dalek Universe, so I guess you could never say never. Won't happen though as his career has moved on, along with the TV series of Around The World In 80 Days he has the film Fuddy Meers in the works and there is talk he may yet return as Kilgrave In The MCU:

https://wegotthiscovered.com/movies/david-tennant-reportedly-talks-return-kilgrave-mcu/

There’s already been plenty of speculation about D’Onofrio returning and making the jump to the big screen, but we’ve also now heard from our sources that Marvel are keen to bring Tennant’s Kilgrave back into the fold, and with the narrative slate wiped clean, they can technically reboot and re-introduce the character without having to worry about continuity. Although previous rumors had pointed to him perhaps playing Nightmare, it seems the studio is more into the idea of having him reprise his Jessica Jones role instead.

According to our intel – which comes from the same sources that told us Netflix were making an Extraction sequel and a new Scream movie is in development – with Marvel set to regain the rights to the Defenders, they want to get the bigger names back onscreen sooner rather than later. And that isn’t just limited to the heroes themselves.

I keep seeing people asking this and some are serious. The show is about change with each doctor bringing something new to the table. I'd hate to see a doctor regenerate back into a previous doctor because we've already seen that doctor and I'd rather see what someone else can do.

I dont mind them retuning for one offs e.g. the 60th although as I've said in another post I'm sick of Tennant as sometimes he gets more focus than the current doctor. While it might sound hypocritical, I'd never say no to a mini series leading up to the time war with Paul McGann

No thanks. I’d welcome Tennant back for a multi-Doctor story for sure, but bringing any previous Doctor back full-time seems silly to me. He had his time. Regeneration not regression!

Don't really see the point. He's had his time now.

If I'm honest, I personally prefer his episodes to what we have now. But they're always repeated on W anyway. The show has always been about change and moving on.

He's my favorite doctor of all time but bringing him back would be silly

I'm still hoping there is some sort of weird occurrence in the space-time continuum during regeneration that throws off the process slightly and the Doctor regenerates as a Gallifreyan chimpanzee (or the equivalent primate with the closest dna to time lords).