Yeah I’d say Linker is a must with Featherfoot, since all the class skills have a short range and/or are single target.
As for the build, I’d say get Sleep at lvl 5 for utility, get Lethargy at lvl 1 for the Slash bonus attribute. Maxing out Energy Bolt isn’t a great choice since the skill is pretty lame later on, but it’s a matter of preference I think. Earthquake is usually kept at lvl 1 as an emergency button only.
Physical Link is pretty pretty bad currently, and not avised to be maxed out. Usually people will get angry at you if you use it in dungeons. So I’d move one point into Unbind.
I’d put more points into Ice Wall, since it combos with a lot of good skills from other classes and is crazy good utility.
Keep in mind Rune of Giants stops you from casting all your skills, you can only auto-attack and jump for stomp damage.
Other than that, it seems pretty neat. Rune of Ice with cryo skills and Linker + Featherfoot should keep things fresh. Keep in mind that Runecaster without Quickcast requries a lot of mindfull positioning though