Not to mention his voice didn't really suit the role anyway. His frail, trusting, somewhat-goofy grandfather voice ... didn't actually believably convey the likes of a hardened war general struggling with a passionless goal and buried internal disillusionment.
I would go so far as to deem his performance verging on mechanical.
Anyway, this is pretty much a nitpicking issue. Most of the voice acting and casting in Skyrim is brilliant. And the music is of course [censored] awesome. But this one casting was definitely a fail.
CCNA: Do Not Bypass the Autocensor.