I agree with you that the Barrowland would be a better venue but the stage is definitely too small. As for the armadillo being the worst venue in Scotland, I would award that 1 to the SECC. I went to see Maiden 3 times last month and the SECC was by far the worst of the lot. The sound in that place is so bad. I have been to a few gigs in the armadillo and the sound is pretty damn good.
Just bought 2 tickets for the Glasgow show (almost £75! Damn booking fees
) Not sure what to expect though, I've never been to a gig at a seated venue. Hope the sound is better than the SECC like you said - Prog Nation 2009 at the SECC was a bit iffy, the bass drum especially.
EDIT:
Here's where I'll be sitting:
Would have been nice to be central, but it's only 7/8 rows from the front and last time I was slightly on JP's side at the SECC, so it'll be nice to get a better view of Myung this time