Keynote Remote Broken on OS X 10.10.3
If you think it's a discoveryd issue and 10.10.4 can't come too soon, might as well make it come now! Go to this Apple link and sign up for the public beta program, where you'll be given a link to download a piece of software that'll get the App Store to pick up beta updates. Take a backup of everything, install Beta Access Utility, and then install and enjoy a discoveryd-free Yosemite!