Here's my list.
I think the 3DS version of Smash 4 is the best version of the game, with a better classic mode, An All-Star Mode that goes in order from oldest to newest franchises, better stages that are more enjoyable to play on even with hazards and gimmicks turned on, Smash Run is fun to play through and is a better way to hunt for customs compared to Master and Crazy Orders, and the online seems to run smoother on the 3DS, with less of the BS that you see in the Wii U version, such as taunt parties. While the Wii U version does have its perks and looks better, the fact that Smash 4 3DS is truly portable helps make it the superior version.
-I think Six Fire Emblem characters is a good number for the series, and if I had my choice, I might even add a couple of more. While I can understand the argument that the series has too many reps, people tend to forget that there are 15 games in the series, all of which have hundreds of potential playable characters with very few ever recurring between games. Fire Emblem has also enjoyed a surge in popularity this generation, going from one of Nintendo's B-tier franchises to a money maker with Awakening and Fates selling millions of copies, and Heroes becoming Nintendo's most popular mobile title in terms of revenue.
Barring Lucina and Roy, the other four Fire Emblem characters also bring their own style of play to Smash, something that would be lost if we cut any of them. Also, on a related note, I will say that Corrin was a great choice for a DLC character.
-I like the Semi-Clones like Dr. Mario, Dark Pit, Lucina, Roy, etc and think they all add something to the game.
-I love the idea of custom moves, which makes it a shame more was not done with the idea.