OK, been a long time fan of Geno, played SMRPG on nearly a yearly basis and have loved the idea of Geno in smash bros ever since the brawl "leaks" I had a few ideas lumbering around for him as a character, and i hope i'm not out of place with my fan ideas (been keeping up with these posts since page 1 but haven't posted yet)
Moveset ideas:
Normals (using establish characters as a base):
jab combo: essentially fox's (smash4) w/out the rapid jab
ftilt: similar to mario's
Fsmash: akin to mii gunner, using armcannon
dtilt: similar to mario's
dsmash: similar to lucario's, but shooting double fists
utilt: similar to falcon's, obviously less range
usmash: similar to megaman's but with the star cannon
nair: spinning attack (like ivysaur's?) using fists
fair: similar to villager's, using 5-finger gun
bair: similar to samus's
dair: similar to megaman's, shooting either one or two fists
uair: mii gunner, using star cannon
Specials:
neutral b: Geno beam. Can be charged and stored (3 levels), shot like rob's, though can be overcharged, if done will auto fire at level 2
side b: Geno whirl. flies at the speed of link's fully charged arrows (size of Ylink's boomerang), continues through opponents with limited range. deals massive damage (like 20%) at the very beginning and end of the attack (also deals massive shield damage at those points), but will do a little less than mario's fireball anywhere else. appropriate knockback
down b: Geno flash. similar to pika's, but has three blasts on either side of geno (leaves a gap directly over him, with 2 on the front of geno with 1 on the back. knock-back hits opponent between blasts ending w/ opponent behind geno), is faster than pika's but does less damage and knockback to compensate.
up b: Geno boost. it was actually hard to think of this one, but essentially geno gets launched upward mostly, like pit's, though Geno gets a small boost to either his next attack or next hit against him.
Final smash: Geno blast. since these normally never appear anyway, I thought it would be better to have this move here than geno flash. Geno hops into the background turning into a cannon and a reticle appears on screen. he fires and a massive explosion appears.
Stage: Monstrotown
flat stage (like wily castle) with two platforms, one in the center and another above it to the left third. there are doors on the topmost platform, the ground beneath it, the right side (same level) and underneath the stage center (but one can just jump back up the the main level). entering any door makes you pop out of the other one (a la mushroomy kingdom's pipes in smash 64) and if you pop out the one under the main platform Culex appears as a boss with each crystal doing different attacks for about 1 min 30 seconds before disappearing* (*he is killable). when he appears, the stage transforms (aesthetically not physically, but the doors disappear) to the same starry background as when you fight him, and the music changes to his boss theme. If he is not defeated, he just fades away and the stage goes back to normal, if he his defeated, then the door under the main platform disappears for 2 minutes. Hazardless version is the same aesthetically but the doors don't do anything with the lower one gone permanently (in 1v1 the stage would transform to the starry background and the music would change if both players dropped to 1 stock each).
TL;DR
sorry for the long post. I just love this character and have had this headcannon for a long time...