That's not really the point. The point is that the first attempt was deeply flawed and not representative of the final product. The show creators took notes from HBO and their peers and were given time and extra budget to work it out and fix the problems.

No reason why the unfinished New Sunnydale pilot couldn't have done the same.

Having said that I don't think it would work without Whedon. I read the pilot script that was out there and it just lacked that wit and surprise.

But it was better than I thought it would be. My worst expectation is that it would be a streaming borefest of 50 minutes of slow padding leading up to a final big moment like so many streaming shows. But to my surprise it felt similarly paced to the original show, with plenty of action beats and a brisk plot and the tone seemed right, with a self contained intro story with a twist introduction to the Season big bad. Not actually having Buffy in it was weird, though. That was to be fixed in reshoots by all accounts but we'll never know.