Tooltips with inline tags only are sad
Whether this is sad or not I'm unable to argue with but it is a no-frills feature that was born out of the necessity to display information within SMW (jQuery tipsy was evaluated and did not support the features required).
The #info parser is an add-on (not really necessary for core but it was introduced some time ago) with a low barrier for technical adaption and is more or less maintenance free.
If a user wants to use somethings else it is entirely up to him/her to do so or if someone wants to submit a PR to improve the #info functionality that would be fine as well but no core developer will spend any time on improving #info because it does what it should do, provide a simple "info" about an entity marked by an icon to indicate the severity.
