Really? Cause I was a beta tester too, and there were a lot of missing features/bugs.
I never said it wasn't missing features, but it wasn't the "end of the world" as you put it. Let's go through your list...
Couldn't burn cds.
Couldn't play DVDs
Yes, both of these did suck. Admittedly though, the issue with playing DVDs was more of a concern for PowerMac users with SuperDrives, since at the time, a huge segment of the Mac userbase didn't even have SuperDrives, and many of those with iMac G3s solely had CD-ROM drives that didn't even have burning capability. If I recall, after OS X's release you started to see CD-RW drives become BTO on the Apple store, but by that point 10.1 wasn't too far away.
For awhile there, you could even pick up Toast for free to help deal with this issue.
You're right, it sucked, but both were remedied via 10.1 that came out approximately 6 months later.
Dialing up with a 56k modem would frequently crash your machine
Honestly I don't remember this issue. During beta testing I remember testing dial-up with the backup number Cox provided, Netzero's free access, and the AOL trial option, without any issues. Don't know if something happened before release though.
It ran dog slow
No hardware window acceleration
This was mostly due to Aqua, and as I mentioned previously, was part of that "slow/poor performance" aspect that 10.1 helped to remedy to a greater extent (though even then at times it would still slow down).
As for hardware window acceleration, I don't recall Appearance Manager in OS 9 having any type of hardware acceleration (and in this regard, I'm referring to offloading the acceleration to the GPU. Not sure if you mean something else).
Honestly, one of my biggest issues was that driver support was lackluster at launch, which meant that at the time I had to re-install replaced components that my PowerMac had shipped with in order to guarantee compatibility. That's what annoyed me a lot.
Look, I loved OS X, but plenty of people didn't, and even I had to boot back into OS 9 all the damn time to get things done (like, as mentioned, burn a cd, which couldn't even be done from Classic.)
It was so bad Apple gave 10.1 away for free. In stores.
Final Cut Pro X shares a lot in common with OS X besides the number, which I'm pretty sure was chosen intentionally as it's following the same development path.
The difference is that FCP 7 hasn't been updated for a couple of years almost and thus is lacking quite a few features already. Apple essentially actively ceased support in order to supply resources to a new version, but yet this new version is lacking features that many find critical.
Now, in comparison, OS 9 still was seeing regularly updates up through and even after OS X's release (likely due to the less-than-desired performance/functionality of OS X). From a "My job partly depends on this" perspective, OS X offered nothing. FCP 7, by comparison, is lacking quite a bit, and from the reviews and responses I've read through, FCP X just wasn't ready.
Apple needed to take Blizzard's approach and "release it when it's ready", instead of releasing a half-baked product.