Never was a Smash fan till Brawl came out, so my hype reveals come from Smash 4, Onward
Smash 4
I remember like 4 months prior to the direct getting Pokemon X for Christmas and choosing Froakie as my starter just because he was the cutest of the bunch... Little did I know, that watching the April Smash Direct would reveal to me that my little frog boi, all grown up would be getting in Smash... Let's just say he was easily the most hype addition to Smash for me so far,
Miis, getting in got me pretty excited because I just wanted an custom character aspect.
PAC-MAN was easily, my most wanted third party character for Smash 4. I remeber accidentley leaving the smash website on my computer all night, only to refresh it and notice that PAC-MAN was added. I Freaked out quite a lot...
I remember when the leaks happened and Duck Hunt was part of it, I nearly freaked out. Deep cut picks are always a ton fun. It didn't help that they were adorable...
I remember watching the direct live and seeing the words "Final Fantasy VII" pop up on the screen and then just being shocked that Cloud was getting in. I'm not really a FF fan, but the aspect of a character with more ties to PlayStation getting in, was pretty exciting...
Ultimate
I knew they were coming, but I'm pretty sure it was how they, along with Ultimate were announced
I knew he was coming, thanks to verg, but doesn't stop him form looking like a super fun character.
I love "No one saw it coming" reveals, and Richter was easily the most notable example of this, also, having the guy who said the classic "You don't belong in this world" in smash is definitely a plus.
I liked Villager a lot in Smash 4, so having a new play style that's still similar in a sense, got me pretty excited.