Change in Doctor Who is always exciting, certainly- look at how changing the companion this year switched up the entire ethos and style of the show, from the Doctor on down.
The worry, of course, is whether the change that Chibnall's going to be offering is much good or not; from the sounds of it, the only common creative link to any previous Doctor Who is going to be himself, and he's not exactly covered himself with glory on that front (my fondness for The Power of Three notwithstanding). It's far too early to tell, obviously, but I'm far more nervous about the advent of Chibnall's Doctor Who than I was Moffat's.
It rubs both ways, because it's easier to write if you have a hook like an existing companion, but also you immediately invite baggage. Moffat begged Tennant to stay for series 5, but weirdly as much as I love Moffat's synopsis for a Tennant-led series 5 & Eleventh Hour I don't think it would've been nearly as successful as it was.
I think a lot of that series' success is down to how completely and thoroughly Moffat nailed The Eleventh Hour.
As Phil Sandifer pointed out, Moffat made a pile of creative choices that frankly could have killed his take on the series dead on the spot had they not succeeded, from Smith's casting on down, and he and his crew aced every single one of them. It's impossible to know whether or not he'd have done so well with a Tennant-led Eleventh Hour, but he wouldn't have needed to- Television's Beloved David Tennant would have done the job for him. I really don't know whether Chibnall has an Eleventh Hour hidden in his locker.
That aside, it's also important to remember a key difference to the Tennant to Smith transition: for better or worse, true or not, the show was a critical and commercial darling, whereas now it's arguably at it's lowest critical and commercial ebb since 2005, where papers who were slavish to it before like the Guardian now call it a snoozefest week in week out, etc. A clean break will help immensely, and I actually think it's overdue - RTD's era got out before it dragged on and 'got old', and though I absolutely love this series I think for a wider audience I think a huge part of the problem is that the Moffat era has gone on about 2 years too long. Maybe 3.
You're absolutely not wrong about this, though, and the time is probably ripe for a more general public-friendly take after the spikiness and weirdness that characterised much of series 8 and 9. We've got that at the moment, but you're right that it's probably too late without a wider, more fundamental change.
As much as I enjoyed series 8 and 9, they were the wrong series at the wrong time. Imagining what a series with the tone and energy of series 10 might have done in 2014 hot off the heels of the 50th anniversary kind of makes me sad for what might have been.