Comment gadget
Fragment of a discussion from User talk:Yair rand/LQT archive
Actually, it seems one can use directly the "wiktionary" prefix, which links to the English Wiktionary (check here for mediawiki's default values, and here for a non-English WMF wiki with a customized interwiki map).
Regarding the indentation, how about indenting the text box as much as the last comment, in order to discourage usage of constructs such as **, :*, etc? The indentation in the preview seems to be working well already; I'll let you know if I come across any edge cases.
Finally, appending a warning under the text box --say, right after the cancel button-- when a signature is added (3 to 5 tildes) would be a nice touch, like LQT already does.