A brief overview of viable-to-semi-viable characters and their place in the meta at high level:
Fox - Still going strong. Worryingly so, but not to a 20XX degree.
Falco - Sucking **** at the peak rn, smart PPesque play is needed to combat the floaty meta.
Marth - Looking fine-ish but also hurting without PP. M2K should play him more, he's the only tournament-threat marth.
Sheik - Definitely not at her best, Armada is really a roadblock for her main man Plup.
Puff - On the upswing at a local level over the last few years. Be afraid.
Peach - Best player in the world swept Genesis with her. She works.
ICs - Up and down, Chu's been making them look pretty good recently but they're getting less and less effective.
Falcon - On the upswing, thanks to Wizzy, n0ne, and S2J all stepping it up recently.
Pikachu - Still waiting on someone to catch up to Axe. Pikachu's a good character, but needs the right hands.
Samus - Hugs has been looking sharp lately, as has Duck. Rip PlupSamus.
Luigi - 3 mains in the top 100, a small reniassance in socal, 5th at a major.
Doc - RIP
Yoshi - Yoshi mains are starting to crack into PRs since aMSa inspired a crop of absolute madmen.
Ganon - Slowly but surely slipping away as we slide into 20XX. Get good at the spacie chaingrab guys
Mario - RIPx2
Link - Sixx put two top 100 wins on the board in 2016, getting 2nd at a fairly stacked european regional. Not bad.
YL - Haven't heard much.
DK - Ringler in Socal's been improving, but DK is pretty straightforward. Don't expect much without a godlike player emerging
Beyond these dudes I'm pretty sure that Melee is as it is, but a player to watch out for that plays a low tier is Zoma, who has a pretty technical and skilled mewtwo and is on the come up according to Rudolph