Should probably annotate that on the spreadsheet if other races are unable to do it because of the bone spikes.
---------- Post added 2013-02-17 at 06:10 PM ----------
The 2 closest to mandatory are GoSup, since usually you will want to have voidy tanking instead of you, and KjC, because mechanics that randomly target players and you have to avoid will randomly target you 100% of the time, but even these aren't mandatory, just highly favorable in most circumstances.