It's true. I got SMG2 for Christmas and have been playing it for a while. But I don't even know what I enjoy about it over SMG1 outside of the better soundtrack. For some reason I find this game a lot more fun than SMG1 which I found to be a little boring. And SMG1 made me hungry all the time too. That's some weird phenonmenon I can't even begin to explain. Maybe I'm more open as a gamer compared to when I bought SMG1 in 2007? I don't know but this is actually a really good game, and the best Mario game I've played since Paper Mario: TTYD.
Speaking of the soundtrack, I thought SMG1's soundtrack was rather boring overall too. The soundtrack in SMG2 is waaaaaaaaaaaay better...based on the strength of four new tracks (one is a SM64 remix track though) mainly, but I also think the Starship Mario theme is nice too. What four tracks though? These:
Slipsand Galaxy's/Clockwork Ruin's music really surprised me. Usually desert themes in games are crap and use generic "desert" or "Middle Eastern" instruments that sound terrible. SMG1's desert theme is an example of this. SMG2 does the same, BUT...get to 1:11 and it's epic. Though I think the build up does get good. My favorite track in the game is probably Melty Monster. That's just an awesome orchestrated piece. And you know what the funny thing is? SMG2 has a much better and more epic orchestrated soundtrack than Zelda: SS which had a rather mediocre soundtrack overall. A few decent tracks but that's it. A Mario game had better orchestration than a Zelda game. Lol. Also Throwback Galaxy is great, very catchy, and Puzzle Plank has great violin.
As for my progress...I have close to 120 stars. Still have the 120 Green Stars to get once I get the last few stars I'm missing for 120 as well as the final two stars in the Grandmaster Galaxy which opens up once I get all the Green Stars.
Btw this game is hard as hell. I vaguely remember having some trouble in SMG1 but this is one of the hardest Nintendo games I've ever played lol. Yeah I'm sure people will say "that doesn't mean much" but I'm factoring in Super Mario Bros. and Metroid. Taking those out this is probably the hardest.
I wonder what they'll do for a new 3D Mario for Wii U whenever that's out. I wouldn't even mind if it was a Mario Galaxy 3 but I think it'll be different.
tl;dr - After being a bit disappointed in SMG1, I find Nintendo did great work with SMG2 though not entirely for reasons I can describe.