3-point Editing Overview
You can use the traditional "I" & "O" keys the same as always - unless I'm missing something (or you're referring to something else".
As for apparent lack of ability to import from FCP or FCE, that's disappointing. But, as others have mentioned - it's still early. For me, I don't have any incomplete projects that I would want to continue in FCPX (or a need to import completed ones), so it's not much of an issue for me. I can always use FCE for those, if needed.
I've been using FCE for many years. Even though it does support AVCHD, it requires transcoding. Native editing of AVCHD is a major selling point [for me] - especially with the new pricing. I'll probably jump on board fairly soon.