MathType 6.7 for Mac OS X has been released. I'm running the "trial" version before upgrading to check it out. I've only done a little messing around, but thought I'd report here on what I've gotten so far. It allegedly works with MS Word 2011, though I haven't actually tested that yet. For downloading it, see here: http://www.dessci.com/en/products/MathType_Mac/
So far I can report:
MathType now has the option to save as Acrobat PDF as well as EPS. This should solve a number of the font and characters-failing-to-show-up issues, while preserving the ability to edit equations from Indesign by using the "Edit Using..." command. (However, MathType doesn't appear in the "Edit using..." command's submenu, so you need to choose "Other" and then point to the application.) However, even the eps files seem to behave better than in the previous version of MathType (see below).
The obliqued Symbol font Greek characters now appear and print correctly from Indesign, which was broken in CS5 up until now. I tested several other characters that have caused trouble over the years, including capital Greek letters and the over-sized brackets, and these all seem to behave nicely now.
The only Greek character sets supported are still the Symbol and Euclid (TeX lookalike) fonts, which mean that all those elegantly designed Greek letters in fonts like Garamond Pro, and the sans-serif Greek characters in Arial and Myriad Pro are off limits. Shoot. I had hoped that they'd add OpenType Greek support, for those of us who care about good typography and want to use those less clunky Greek characters that match the text fonts we're using.
The "Insert Symbol" command still only shows 256 characters, so you can't get at the Greek (or any other special characters) in OpenType fonts that way either.
So, although it's not all I'd hoped for, it does look like MathType is functional for Indesign once more. If anyone else has had other specific problems with MathType and Indesign in the past, please try it out and report back.
Rodney, thanks for the brief review of MathType 6.7. What you point out about OpenType support really is more generically related to partial Unicode support. I could give reasons why it's this way, but I suspect what matters more to you and other InDesign users than the "why" is the "when". I can't answer the "when" question other than to say we're fixing it with a new Font Manager. We're working on it, but I don't have an idea of when you can expect to see it.