With sequels it's all about context. Yeah there's a lot of interest in Pikmin 3 but there are only two Pikmin games. The series is very new. But if Nintendo revealed Pikmin Puzzle League the same people wanting Pikmin 3 would roll their eyes. Earthbound? There's only been one Earthbound game released in North America! Of COURSE we want a sequel! Just getting the Japan-only games released here would be a big deal. And Kid Icarus has been quiet for like 17 years. Though I think people asking for that one really don't know what they're asking for. I have no idea how a 3D Kid Icarus would play.
Not all sequels are equals. Heh, that's pretty catchy.

Mario is pretty played out in the spin-off department. The only thing I can think of that they could reveal at E3 regarding Mario that would be a big deal would be Square Enix working on the next Mario RPG or another platformer though it would be pretty soon for one. I think when people say "lay off the sequels" it's the "let's shoehorn Mario into this game" type that they mean. Or the Metroid Prime Pinball and Link's Crossbow Training stuff that seems like a shameless cash-in an a franchise that had previously remained very "pure" and is taken very seriously by fans.
What anyone is really asking is for Nintendo to release interesting games. Mario Curling isn't interesting. It's generic product. New IPs are naturally interesting because they're new. Certain sequels are interesting because it's either a franchise that has long been dormant or one that is stilll new enough that the formula hasn't been stretched thin or is of a series that is such a big deal that sequels come out years apart, sometimes only once per generation, and each game significantly ups the ante every time (ie: every release in the series is an "event").
That's backwards to what Nintendo does. Unless they're intentionally setting out to make a sequel, Nintendo makes the game first, then as it takes shape decides whether it would be a fit for a current character, or if they need to create a new character for it. They don't seem to want to create new franchise characters unless they have a game that doesn't fit their existing ones.
This is different than Nintendo of old and I don't like it at all. Today's Nintendo would have made Metroid Space Racing instead of F-Zero and Mario Jet Ski instead of Wave Race. In theory Mario, Samus and Link could probably be shoehorned into EVERY Nintendo game if you think enough about it. Samus could fit all sci-fi style games, Link could fit all fantasy themed games and Mario could fit everything in between. That's the problem with this attitude. They would never have the franchises they have now if they had this attitude years ago.