The show has a slightly bigger scope, but to me it hasn't strayed too far from what we saw last season. I'd say the music videos are getting more elaborate, and in some cases it hurts the song. For example, in Ep. 6, the "Same Girl" song worked just fine. It was done very simply and I could pay attention to the lyrics. The "Weapon of Choice" song, not so much. There was a lot going on and I still couldn't tell you what half the words are because of the audio mix. I certainly don't mind re-watching the show but, still...
The songs themselves are better integrated into the show, although some of them don't seem to work as well on their own. The guys have done a tremendous job writing so many songs in such a short period of time. They may not live up to everyone's expectations, but that's only because the bar has been set so high. Obviously some fans will always prefer the old stuff, which is fine because it's not going anywhere.
As for the newer material working in a live setting, I guess we'll see when the new tour starts. I'll be there, scowling at them and judging them harshly.
What I'm really wondering about is what new goofy-looking instruments they'll bring onstage. The new songs are much more musically diverse and I wonder how they'll sound live. The new album / Season 2 soundtrack should be very interesting to listen to.
The supporting players are getting more involved this year, which is fine by me as long as they don't take over the show. Sometimes they use Murray a bit much for my taste, and since he's hilarious, I don't want him to wear out his welcome. I've also liked everyone's participation in the songs too - "Hurt Feelings", "Stay Cool" and "In My Dreams" are some of my favorites.
Some other thoughts about the season in general - I think Bret & Jemaine's acting has really improved and they've both shown a lot more range than we've seen before. Not that I mind them when they're acting dull and mumbly...
One good thing about the bigger budget is the improved cinematography. Just look at the difference between the very first episode and the latest one. People don't look yellowish, sweaty and distorted anymore! However, I don't have HD so I can't comment on that.
If this is the last season, I'll be happy. If they continue, I'll be happy. Just as long as they don't drag it out until I want to grab a shotgun and put the show out of its misery.