I am currently planning to update the server to 1.10 - with a full wipe sadly. Looking at the logs, not a lot of people played in the last days, so updating it with a wipe wont hurt a lot of people. Switching to a Sponge-based solution enables slightly more performance and that 1.10 update.
But now we come to the magic question....
What mods should go away, what mods should stay in?
I have the obvious Buildcraft, IC², TConstruct, Extrautils on my list - but what else?
Galacticraft will go - not updated and noone really went there. What about ProjectRED?