It crashes if you use Optical kerning. It looks ugly! if you use Optical kerning. Don't use optical kerning!

However, I would suggest this not as a policy, but as a troubleshooting technique. If your hangs and/or crashes stop happening as a result of forbidding optical kerning in your workflow, then at that point it can become a policy, and hopefully a bug report to Adobe as well.

I think I recall someone trustworthy, maybe Thomas Phinney? explain how it was supposedly useful when setting text at large headline sizes, if the designer's kerning pairs were intended for text set at body-text sizes. It was in a discussion about the profusion of faces in recent Adobe fonts, where there would be a Captions set, a Headlines set, and so on. Speaking personally, I hate the way optical kerning looks on body text. Old people (in my job, that mostly means old Russians) complain to me that it's harder to read; someday I'll do a readability study. Tightly-set text is, I think, harder to read, and leads to lower comprehension, and designers tend to use optical kerning as a shortcut to fit more text in a given space. This is opinion, once again, but it's my opinion derived from handling the work of hundreds of different designers over the last decade in a translation firm.

Finally - so, you're doing Sanskrit transliterations, no? That's the only place I can recall seeing n with dot above. I suspect that no one at Adobe has ever tested anything related to this area, so you're more likely to find bugs. Is it just Minion where this happens? Hmmm... even in Word, n + combining dot above looks wrong. I suspect it's an issue with the font, not with InDesign. You may need to pick a different font - I think that there are some URW fonts that have been released for free public use for Sanskrit-transliteration stuff.

Well, as I'm sure you already know, metric kerning means "the font designer decided that glyph x and glyph y should be separated by thus-and-so distance." Optical kerning means "InDesign's font rendering tech is using an algorithm on the curves in the font file and generating what might be an optimal distance." Of course, there are quite a few ways for those curves to be stored in a font, and I've noticed that different font foundries use different techniques that work better with different font rendering techniques. I.e. Adobe fonts don't always play nice in Word, and generic MS fonts often drop when texts using them are placed in ID. I do a lot of Vietnamese typesetting, and combining accents can make my life quite difficult sometimes.

I believe that the cause of the variation you see between metric and optical kerning has to do with how the font is made, and how it gets rendered by ID. The team that makes Minion is not the team that makes InDesign, so I guess you are seeing a failure of Adobe upper management to make sure that the work of team x functions well with the work of team y. There are some kinds of InDesign work (academic work requiring really good footnotes, typesetting languages that aren't Western European or Japanese, database-driven XML workflows) where we see those failures more often, because there are fewer of us, and so Adobe does less quality assurance work on our tools, and there are fewer of us to file bug reports.  A bug report submitted to that link will not get any response - if you want to hear back from Adobe "Yes this is a bug, we'll work on fixing it" then you'd need to file a support case.

And I think that the only place where you might be confusing is: I am more-or-less sure you are not asking a question, you are making an observation. If I'm wrong let me know