I have only played a couple 2 hour sittings of RB3 over the week and to me it seems like the difficulty went down. I have been getting gold stars on most of the songs in the game, expert drums. I played a couple of the nightmare songs and some of the nightmare songs are very tough but others not so much. As for the rest of the songs its pretty basic as long as you know your patterns.  I don't remember getting so many gold stars, if you hit 97% or more you will most likely get a gold star. I don't know if my skills have increased in uber-ness but i checked out the rankings so far and some how i managed to get into the Top 2% for drums in only investing maybe under 8hrs of playing. Rock Band 3 seems to be more forgiving this time around whether it has something to do with the track list because of pro mode being added.
As for the ranking system i will wait a couple more months to see if more players start to ranking up because the game just came out.

 Did anyone find Rock Band 3 easier or harder then past games? Are gold stars easier on other instruments as well? 

I think it really just depends on the song. Before I forget is one of the tough ones. I think for this game they were trying to balance out the instruments, like have some really hard at guitar and other hard on keys. Of course some instruments get the short end of the straw and have really easy parts (Expert Keyboard being one). I'd play a few times and goldstar the song lol.

Without trying to sound like a GH kid... I managed to 100% the solo in Caught in a Mosh on a sight tread.
 
Eff 'easier'. I feel like a superhero :D

Another part of it might be that... this is the third Rock Band game, so I've (or we) put in plenty of practice playing through the last two installments. I'd say that Rock Band 3 has plenty of difficulty for each instrument. Crazy Train's solo is nuts compared to Green Grass and High Tides, and still that's a metal song compared to a southern rock cover. You also have your Smoke on the Water but I'd say it's about on par with Rock Band 1 and 2.

I find that by adding the extra overdrive for solo play has made getting gold stars a lot easier.

I talked to my brother about this tonight. He's been a big Rock Band fan and he's a rather good drummer. He said that while he could gold star some of the earlier songs overall he's been finding Rock Band 3 harder than Rock Band 2.

I am personally bored with 5 button guitar. I've been playing it since GH2 and on expert since the original Rock Band. Try playing a different instrument if you think its too easy. Pro keys is incredibly fun to learn to play. Unfortunately PS3 pro guitars are delayed a month so I can't get into that quite yet.

Easier is okay by me.

I find it much easier to fail in this game.
 
I could be wrong, it may just be that I'm not noticing I'm going into the red. Go play a song you would barely scrape/hack through on RB2 and get back to me :)

" I find that by adding the extra overdrive for solo play has made getting gold stars a lot easier. "

It is quite a bit more overdrive than solo players are used to getting, so I definitely agree that it's a major boon to your score (and therefore star count.)

TC, if you're finding Expert Drums too easy, then you should probably start playing on Pro Drums. I imagine the cymbals add a whole new layer of complexity. The Pro mode is there for those who have mastered the original RB instruments, and it sounds like you're quite good at the Drums by now.

The only song on a Rockband disc that's ever given me any trouble is 'Green Grass and High Tides', and that's only because there's no video calibration.

Bout the same...buuut the new pro modes for drums and the keytar are a nice new challenge :)

People have to remember that you weren't as experienced playing these games as you are now. I remember when people were saying Guitar Hero II was easier than the first game, when Guitar Hero II probably has some of the hardest songs of any of these guitar-based music games ever. The difficulty seems about the same but since you've been playing so long you are probably gold starring songs very consistently, I know I am. If anything they could have just made gold starring easier for the regular instruments since the main challenge this time is in the pro stuff.

In stark contrast to seemingly everyone else, I'm finding Rock Band 3 (Expert Guitar/Bass) quite a bit harder. I could play every song in Rock Band 2 without failing (sometimes Visions got me, but basically I could beat it) and even got Gold Stars on Green Grass and High Tides, but I've been finding some of the later RB3 songs super tough. That Llama one, for example, is nothing short of a bastard, and there are at least 3 more that I've yet to get through without someone saving me. 

I could be wrong, but it seems like the timing windows are a bit looser in RB3. I was playing some fast beats on drums and I was actually keeping a combo in spots that I would think that I wouldn't while playing the same way in RB2. So that was weird. Maybe I really was keeping up though, I'll have to play more drums and get a better feel for that stuff.