Very well sadi! I agree 100%.I think a part of the "bummed" emotions we're seeing is due to the single-artist weeks that have dominated Rock Band DLC for quite a while now. Basically, the announcements each week will have become an "all-or-nothing" event now. You'll either be happy with what is announced and will be greatly anticipating the following Tuesday, or you'll not like the one artist/band and have to wait another week in the hopes that you'll get something you want.
In releasing multiple artists/bands in one week, even if it is just one song from each artist/band, there is a much greater chance that you'll see something you really do want. (See the Two Tickets to Paradise/Drops of Jupiter/other-song-I-can't-remember-right-now week).
So the bumming that's going on with this Blitz announcement is likely due to the fact that if Iron Maiden isn't your cup of tea, the complete lack of variety in the announcements this week has amplified the down feelings. Had the artist that was announced for Blitz been something other than Maiden, there would at least have been a statistically greater chance that it might be something you liked.
So in my mind, I think that announcing a completely different band would have created a greater chance of people getting excited.
Personally, I've just learned to not get excited anymore for DLC announcements. This way if there is a release that I'm hoping for, I won't be disappointed when it's not announced. (Which, sadly, has started happening a lot lately. Prior to RB3's release and for quite a few months afterwards, the bevy of "Classic Rock" and 80's/hair metal bands had me looking forward to each Friday's announcement for quite a while. Currently, it seems like the songs coming out are reminiscent of the modern-era heavy releases when RB2 was the latest game).