I like everything about SuttaCentral – literally!
I would just like to see footnotes to the suttas (as there are on Access to Insight, or the printed Nikāya translations). Sometimes notes and footnotes shed light on some tricky passages or terminology, without which one might get confused or simply not understand or misunderstand the said passage or term. They also often include excerpts from the commentaries.
I myself have the four Nikāyas with all the footnotes, but other people might benefit immensely if the suttas on SuttaCentral also had footnotes.
Just a suggestion to improve the site!