Of the two, I prefer the expertise option, though it's still no where near as good as 4e exploits were. The 'aura' option is too much like the 3e Marshall's "grant all allies in a radius your choice of a trivial bonus."
The Skald's aura is better, for an aura, it has a basic healing function with a neat twist, and dovetails nicely with a variety of spells and exploits.
Aren't we used to mechanics in Next being a lousy version of 4E at this point?