I miss relations as well (and Do-Dai a little, though not so much), but I'm otherwise happy with the song list for the most part. I get the feeling they just needed reasons to reuse footage from Shiny Festa (though when why DREAM?).
I haven't gotten far enough to run into Leon or 961, so not much to say to those questions, Metal.
So far, I think I like this game a bit more than iM@S2, in that doing things, once you actually figure out how to, is not NEARLY so tedious as it once were. (It probably also helps you can do more than one or two things at any given period.) Getting high idol rank though, THAT looks as if it'll be a pain.
I'll give a bit of information based on the bit that I've played so far; I'm still at E3 idol rank. My Japanese knowledge is minimal, so I may have missed things others could tell right off the bat.
All the basic costumes (that is, the six that come with the game from the start) add +10 to just one stat (Floral-Vocal, Luxury-Dance, Starry-Visual).
Flowerish Flowery, if you have access to it, adds +10 to Dance and Vocal each.
I haven't unlocked/downloaded any other costumes yet at this time; I have not checked the stat boosts on accessories too closely at the moment.
On performance gameplay -
Ritsuko's Burst is 5 Vocal/2 Visual/3 Dance - if they cut off last appeals for very slow songs, she'd lose her fifth vocal appeal.
Iori and Chihaya's appear to be as they were in iM@S2 PS3. (As these were the three I chose, I can't speak a whole lot on the others.)
I find that, in general, gameplay is A LOT more fast-paced. If you're used to having a small "breather" point after your memory appeals, you should probably start getting used to NOT having one, lest you wish to lose chain bonus. (Yet I find there's a small breather before burst appeals. Hm. Burst appeals are also much much shinier than in 2, too, if you're a person who likes or hates that sort of thing.)
There's no Danketsu/Unity Score (at least something apparent, anyway), so it seems like burst scores are directly based upon your unit's stats. I noticed that despite a high multiplier on Visual while using Iori's Burst, her Visual bonuses were really low - I hadn't yet done lessons, and Chihaya/Ritsuko are not particularly known for high Visuals. I question the effectiveness of using a dual-stat setup in this game due to that...
Festivals... I haven't yet figured them out, so I can't say a lot about them at this point. Duo and trio appeals seem to be Skills, though, if I'm to believe the idol skill board.
EDIT: ...should we actually start working on making a gameplay-focused thread?
