Swappable redundant power supplies in the cnMatrix ISP 24 port switch platform. These could be AC or DC or one of each. i.e.: manufacturer M's CCR 1072 power input options
Having both AC and DC input options would be great. Especially a -48v version
We also run everything on DC these days. No DC input is a non-starter for us too.
Swappable AC / 24VDC / -48VDC would be really great for being able to use the same switches in multiple different locations without having to stock a bunch of different equipment. Even if it's like Mikrotik's new "PW48V-12V85W" upgrade for their Cloud Core routers where you have to replace a board, it still would let us to keep the amount of different switch models down.