Sure things (100% chance of at least appearing in some form):
1. Zelda U, subtitle revealed, release date revealed in the holiday 2015 timeframe, trailer, possibly a playable demo
2. Star Fox U with finalized title, trailer, release date before Zelda, probably late fall
3. Xenoblade Chronicles X, final trailer, playable, release date before Star Fox, probably late summer to early fall
4. Yoshi's Wooly World, anything not revealed in Spring directs revealed now, playable, release date early to mid summer
5. Mario Maker, ditto to Yoshi
6. Project Guard and Project Giant Robot, more details, release date and playable if small titles
7. Fire Emblem: If, more details, possibly dated for early 2016 to spring 2016 in the west
Probable things (<100%, >66% chance of appearing):
1. Devil's Third, new trailer, new details, possibly a release window, unlikely but not impossibly a release date and demo
2. New mainline Pokemon, X2/Y2 or Z, first trailer, maybe some release details, maybe this year
3. Rodea, western release date, or at least a window
4. Some sort of New 3DS exclusive, hard to say what
5. Multiple uses of amiibo, possibly new figures or a new series (Zelda series, if Nintendo wants to shut up and take my rupees)
6. A spinoff of a major first party IP
Maybes (<66%, >33%, or hard to place otherwise)
1. Metroid 3DS, trailer, release window summer 2016
2. Metroid U, teaser, release window holiday 2016
3. Retro's latest project (maybe it's Metroid U?)
4. Fire Emblem x Shin Megami Tensei, either shown in some fashion this E3 or cancellation announcement by the end of the year
5. Animal Crossing U, depending on how far along it is (another good candidate for a new amiibo series)
6. Pokken Wii U, 2016 release
7. Project Treasure, if Bamco is ready to talk
8. Splatoon DLC, unless the game somehow isn't out yet in which case 100% chance of all details revealed and playable demo
Long Shots (<33%, >0%)
1. F-Zero, in some form, maybe even a new game
2. Earthbound/Mother IP finally utilized, probable just western VC localizations at best, though maybe some kind of localized collection
3. Paper Mario U announced (I see this happening next year if at all, though I do think it will happen then)
4. Fatal Frame localization
5. Bravely Second details (I see this waiting until later this year)
6. New 3D console Mario, of the "star hunting" variety
7. Long awaited 3DS localizations like Dragon Quest
That should be about 75% of the show, plus some indie and 3rd party reels. It'll be a digital event, with a smaller press release sort of event to use that theater they reserved for 299 people. That theater may be used to show off Zelda (crosses fingers).
