As shown in the links provided? Yes.
Yes, Ray-01 has a chance. Ray-01 even has, arguably, a greater chance than most of the choices (...
Goomba!?) people have been throwing out as of late. Let's consider the following:
-Ray-01 is a First Party character from a known franchise spanning five games over the course of four of Nintendo's most prominent consoles.
-Ray-01, and Custom Robo at large, has had representation in two Smash games (Melee and Brawl) in some form or fashion.
- Custom Robo has a dedicated Japanese fanbase (and a Niche one here in America; predominately thanks to the Gamecube game).
-The second game in the series,
Custom Robo V2, received a virtual console release on the Japanese WiiU E-Shop.
-- I'd
even argue (and
have argued earlier in the thread) that
Custom Robo V2 has a solid chance of being included on the Japanese version of the assumed Nintendo Mini that will eventually be announced.
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More information for you to consider:
- Donkey Kong Country 3's trademark (shown in the first link) has been dead for years, but the game received a port and its main character, Dixie Kong, lives on and has a solid support base of her own!
- Punch Out has an expired trademark (shown in the first link), but it received a new title and Little Mac has skins that represent the game which the expired trademark belongs to (the arcade wireframe versions).
- Ice Climbers are unlikely to ever receive a new game...at least, one as we know the original game to play out (See: Kid Icarus: Uprising). But they have appeared as references in a few other games, and are fan favorites in Smash.
- Kid Icarus was "dead" for
Two Decades until Pit appeared in Brawl, and eventually we saw the creation of
Kid Icarus: Uprising.
- F-ZERO, a big name for Nintendo fans, has not received a game in nearly
fifteen years (sixteen for western audiences), and has had a similar amount of games released under its name as Custom Robo (not counting remakes or ports). F-ZERO also has an expired trademark..and is not to be mistaken for the F ZERO trademark...The dash or lack thereof is important. But the franchise remains relevant in Smash and the want for a new game is known by Nintendo. The reasons for this are a whole 'nother topic.
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And this all brings me to
Metroid. Poor, sweet, Metroid.
Metroid was in a similar state as F-ZERO for awhile. It's last 2D outing prior to 2017's
Samus Returns was
Zero Mission (2004; same year as
Custom Robo Battle Revolution on the Gamecube). The last 3D game was
Prime 3: Corruption (2007; same year as
Custom Robo: Arena). The franchise then had a hiatus for three years...and gave us
this. Six years after
that ordeal, we got
this. So, for Prime Fans, their last game date syncs with
Custom Robo: Arena's wait time. Meanwhile, the wait for 2D fans was right there alongside the release
Custom Robo on the Gamecube. Thankfully, we got
Samus Returns, and
Prime 4 is on an unknown horizon.
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So...yes. Ray-01 has a very good chance. Not the best, but good.