Piranha plant was a lame addition. Perhaps I'm missing something, but the reception for the plant seems to be mostly positive. Just go on to any YouTube video, or look at at the main SU discussion page & you'll see nothing, but praise for the character. "Well, looks like I found a new main.", "Piranha plant is our lord & savior.", "Don't you dare insult Piranha plant senpai.", etc... Even in this thread, people have been singing its praise. I honestly feel bad for the fan-bases for certain characters since this isn't the case of a low effort clone, or echo. Nope. Their highly requested character just got beat by a generic Mario enemy that you, "Never knew you wanted until now.", just because of, "Hurr Durr WTF Sack-Of-Rai."
Also, the World of Light mode doesn't look that fun. It's giving me major Smash Tour PTSD, and just seems like a large gauntlet of event challenges. I'm really hoping there's more to it than what they've shown (more cinematics, dialogue, Melee-esque platforming sections, etc...).