[dspillett]

> At least HTML retained <i> and <b> when it introduced <em> and <strong>.

That is not as practical with markdown though, as you are working with a limited set of practical character combinations.

> Styles, like words, can have several meanings

This is one of the reasons why there are many markdown alternatives that behave slightly differently: not everyone writes plain text mark-up with the same intentions.

This isn't something you can solve with a single markdown version, so we have to accept that each could, and probably will, work a little differently.