I don't know if I'd go that far. There have been instances in the past where two veterans were revealed less then a week from each other.
You mean like Little Mac on February 13th and Diddy on February 21st?
You're right. It doesn't mean anything, two character reveals are still possible.
I'm however not convinced to see Yoshi being revealed in relation to the japanese release of Mario Party: Island Tour. In that case, Wario seems more likely at least to me.
Also: I don't think we will see Yoshi and Wario this month. Therefore it wouldn't be a bad idea to think about who's left for a random reveal? (meaning: Who doesn't have a chance to promote anything?)
SSB64:
Yoshi (Yoshi's New Island release in Japan has yet to come and Yarn Yoshi should also be released in 2014 probably, so there are two good opportunities to reveal Yoshi without even talking of possible Mario Party:Island Tour related or Mario Kart 8 related reveals)
Captain Falcon is possible
Jigglypuff too
same goes for Ness
-------------------------------
Melee:
Falco would be an option, especially as I expect Falco to be revealed before Wolf
Ganondorf (not sure about him, he could easily be shown at E3 when Zelda U will get its first trailer)
Ice Climbers
Mr.Game&Watch
Pichu (no comeback expected)
Young Link(no comeback expected)
Dr.Mario(no comeback expected)
Mewtwo(as he is the only one who could return from the cuts, we can expect a special threatment for him and therefore a random reveal seems not plausible yet)
--------------------------------
Brawl:
R.O.B.
Meta Knight (while Sakurai mostly ignores releases in the West, he may handle it different for his own franchise: Kirby)
Wolf (while I can imagine Wolf as a random reveal, I can't imagine to see Wolf being revealed before Falco)
Pokémon Trainer
Lucas (same as for Wolf, I expect Ness to be revealed before Lucas)
Snake (he would be definitely revealed during either a Nintendo Direct or at E3)
Wario (He could be revealed at the japanese release of Mario Party:Island Tour as well as at the japanese release of Mario Kart 8, maybe even revealed for the GBA virtual console)
----------------------------------
Just my two points after all.
Reduced version of this. These are the characters I could see in the near future being randomly revealed:
Captain Falcon, Jigglypuff, Ness, Falco, Ganondorf, Ice Climbers, Mr.Game&Watch, R.O.B., Pokémon Trainer.
I would even go that far and expect a retro to be revealed soon as we have no single retro character until now. Pit isn't a retro anymore since the release of Kid Icarus: Uprising.