Basically, this Smash is obviously showing it wants to rep new series, that's why we have characters like Wii Fit Trainer, Villager, and Little Mac. Pac-Man and Megaman also but they're third party so they might not count.
Anyways, there's ONE character I'd like to focus on, and that's Wii Fit Trainer, more specifically, the series he/she comes from, Wii Fit. Wii Fit was originally shown as the Wii Health Pack in 2006. Xenoblade's development started in 2005. So, they started development about 4-6 months or so apart.
Unlike Wii Fit Trainer, Shulk is one of the most requested characters IN THE WORLD. I'm not even kidding. He's the most requested character from an unrepresented series in Japan (
http://www.gamefaqs.com/boards/633202-super-smash-bros-for-wii-u/64873505), and he gets a good amount of mentions here too.
Shulk's series is one Nintendo is definitely promoting. Hence X's name change from X to Xenoblade Chronicles: X. Putting Shulk in this game would be free advertising for the entire Xenoblade series.
Sakurai has shown he's a fan of Xenoblade in the past. In fact, he's actually tweeted a photo of the Monado! He also happens to be friends with the wife of the director of Xenoblade Chronicles. Also, Monolith Soft has been a huge developer for Nintendo recently, and even helped make Brawl.
Now, one of the biggest arguments against Shulk is that "he's another generic animu swordsman", however, this is only wrong. Shulk has the potential to be one of the most unique characters in the roster, and uniqueness is obviously something Sakurai is shooting for, he even said, "“The biggest feature we look at in Smash Bros. is, ‘What does this character bring to Smash Bros. that other characters don’t?’" Shulk could bring 3 unique move sets to Smash Bros.
Shulk could have a moveset revolving around Break->Topple->Daze, which was a pretty big mechanic in the game.
Shulk could have Buff-based moveset, considering he was an offensive-support character in Xenoblade. Monado Enchant could boost his damage, Monado Speed could make his movement faster, and Monado Shield could reduce the amount of damage he takes for a while.
Shulk could also have a moveset based on activating the Monado, once again a pretty big mechanic in Xenoblade.
Someone even made a moveset for this. (
http://www.gamefaqs.com/boards/633202-super-smash-bros-for-wii-u/69674104)
So, yes, I think Shulk will be in Smash Bros. He's an obvious choice, just like Palutena, Little Mac, and Megaman.
TL;DR Yes, I think Shulk will be in Smash Bros.