I've never seen the first issue, though I don't post nearly as often as some of you :) I'll check the TinyMCE developer forum and see if anyone else has reported this.

Regarding your second request, you can still use forum tags even with the advanced editor in place. Feel free to build your nested quotes manually if the editor makes it difficult to accomplish exactly what you want. I also found some code that would allow users to toggle the editor on and off; I'll take a look at implementing it.