Marth being top tier at any rate is a very interesting idea and as Dabuz said, he's starting to see some serious results including wins over Nairo and Mr. R.
I think a lot of people assumed when Smash 4 came out that he was terrible because he is SO MUCH worse than what he was in Brawl/Melee.
But what we all failed to realize is that just about every Brawl top tier got nerfed hard and Smash 4 toned down OPness a ton in general so a seemingly tame character can be really good in this game.
For some perspective Diddy is still considered top tier in Smash 4 despite only having 1 banana that disappears on hit/block and loses to most moves. In Brawl he had two that didn't vanish on hit/block and beat most moves cleanly and he had an infinite zero-death with a single banana (Zinoto was infamous for it) + extended glide toss dual banana combos/confirms. Despite all this Diddy was only considered 4th at best in the game.
So while comparing Marth to his previous iterations makes him look mediocre, relative to the rest of Smash 4's cast, he might actually be pretty darn good and had we always just looked at him as a Smash 4 character as opposed to a drastically nerfed Brawl/Melee one, he might have been rated a lot higher from the start.
Then add massive Sheik/Diddy/ZSS nerfs and suddenly Marth looks even better.
Like, to explain it this way - ZeRo is a better player than Ranai, and he was out for a significant period of time, and he came back and had to cling to life against every top player he fought against sans Nairo at GOML. It should've been "easy" for him to beat some of the players he struggled against, but it wasn't, because those players got better in ZeRo's absence and one of them (Ally) ultimately reverse 3-0'd ZeRo into second place.
Players have gotten better in just the last several months, and Ranai has had an even more extensive absence, with his brief performances at tournies being considerably poor compared to his max potential we had seen. I question his ability to go the distance because he's going up against players who have all gotten remarkably better and most of which who've had insanely good runs the last few months.
-Trela, in spite of his CEO bust, has bodied all of SoCal's regulars.
-Wrath is probably the Southeast's best player at the moment and has done remarkably well at numerous tournies, including a 13th at CEO, and a win on Ally that forced Ally to go Cloud on the runback.
-Nairo's loss to MJG in September of 2015 doesn't say anything about his chances now, nearly a year later.
-Abadango has had consistently good performances at majors all year outside of his start at G3. He's one of the most consistently good players when he comes to the U.S., in fact.
I could see Ranai losing to any one of them, and while I'd love to see Ranai succeed and I'd love to see Villager be seen as a dangerous meta threat again, I'm leveling my expectations and considering the (imo likely) possibility that Ranai won't do very well compared to his best. Add onto all of this the fact that upsets are happening on the regular, and you have a recipe for him plausibly getting the dreaded unexpected 49th.
Ranai's situation is not the same as Zero.
Zero uses Diddy and Sheik. With or without Zero being at tournaments these are probably the most commonly seen characters are high level play outside of maybe Cloud. You bring up Ally's win over him but Ally plays Zinoto all the time, he could get better at the matchup despite Zero's absence. Larry also lost to Zero several times before he finally beat him.
When it comes to Villager however, no other player comes anywhere near the level of Rana going off results. So he has matchup inexperience at that level on his side. Nobody is practising/studying for Villager as he's not seen as a tournament threat if Ranai is not around.
Now add Evo being B03 giving his opponents even less opportunity to adjust to him. And Smash 4 is not a game where you can steam roll mid tiers (if that's what Villager is) with zero MU experience.