I feel western titles will be represented in Smash as let’s face it, the west is really what’s supporting Nintendo. Ubisoft and Bethesda jumped onto the Switch train far before anyone else with the only notable exception being Sega. Square, Capcom, and others all played it super safe till the Switch was proven a success, whereas Yaht Club, Ubisoft, Wayforward, and Bethesda announced major support on day one. Heck, even Microsoft supported the Switch and has been supporting far more than any Japanese developer as they gave it an entire service. To say the least, the West loves Nintendo even more than Japan seemed to as many of their “allies” that got characters in Smash quickly went to PlayStation when given the option.
My next claim would be that Nintendo has branched out to Western developers, making the language barrier a non-issue. Nintendo has weirdly enough, given more benefits to its western developers than its Japanese ones in recent years. I mean look at what they’ve done for them; localizing Shovel Knight in Japan for Yaht Club, giving two of their successful franchises to Ubisoft, giving Bethesda and Microsoft Mario and Zelda respectively for costumes in Skyrim and Minecraft, and even working with Microsoft for cross-play. It seems their western friends get a bit more love than Japanese ones like Square.
For my final point, I think Sakurai should be mentioned as he has actually praised western developers. The first one being Undertale, then he went off about the importance of Doom, and then him and Nintendo have praised Minecraft with Nintendo employees even being mad that they didn’t create it first.
I think it’s safe to say that we will be seeing some Western 3rd party in the fighter’s pass, as quite frankly Nintendo is running out of iconic Japanese characters to pull from that would leave a huge impact. Add in that many western titles such as Minecraft are popular in Nintendo’s home country and give Nintendo the much needed support, and yeah, I do believe Nintendo will have to break out of the Japanese and all mentality going forward.