Given that 2.3 was in the making for what, 2 years, I really don't think 2.3 has been moving too fast. In fact, I'd argue it's been too slow.
There are always issues that only show their ugly faces after a release and people
really start working with things in production rather than quickly testing things in a controlled dev environment. A brand new design and a lot of improvements under the hood are simply going to result in bugs to be found as people start using it. No amount of testing in dev environments can beat actually using a product from day to day.
Also, the issues you mention have all been fixed in the source and are due to be released as 2.3.1 very soon (this week, possibly today). Or is that too fast?
As for many extras don't work? None of the extras I personally maintain have so far needed an update to fix it in 2.3; the only things I've released updates for were design tweaks to make them look better in 2.3. 2.3 is for 99% a backwards compatible release with 2.2. There are a couple extras that used the 1% that did change and as far as I can tell, the developers affected have been busy releasing updates for that.
There's no denying that some bigger extras have had issues (I'd say primarily Articles and Babel judging from the discussions) which doesn't really say anything about the core. Extras as big as those need someone to lead it, and it seems both of those extras have been largely abandoned and don't have people actively working on it.