Yes, he's small, but I think he stands a good chance. He's ripped. More ripped than other guys of his height. Evan Bourne has really toned abs, but Ki has more muscle mass. Plus he flat-out looks like a scary man. That's not a work, I don't think I've ever seen him smile. He has the eyes of a killer, and his kicking ability will give him instant credibility. His kicks will make CM Punk look like a novice. Oh, and he can "jump out of the gym", so he has that going for him too.
I honestly think he combines the best of Evan Bourne, Bryan Danielson and CM Punk, three guys who have come up from the indies and made it in the WWE to varying degrees. The first two are short, and Punk doesn't have the best body going, and yet all three were signed up and as I said, have all achieved some level of success. Danielson is officially bigger than NXT, not just in terms of how much the audience care, but how much creative care, and if you try and argue that point, you're a moron. Punk has won endless gold and is one of the biggest parts of Smackdown every week. Say what you want about Bourne jobbing, he has a huge fanbase, sells a lot of merchandise, and whenever they give him the go-ahead he knocks it out of the park. Sure, he doesn't get used every week, but I don't think he's in any danger of being released whatsoever.
So if you take Bourne's leaping ability and muscle tone, Punk's martial arts ability, and Bryan's technical and submission skills, add greater muscle mass than any of them have individually and a grade-A intense look, and you have Low Ki.
But what to do with him? Well, before Mercury joined the Society, I was determined he would debut as CM Punk's Straight-Edge Soldier, his Pure Assassin, his Perfect Weapon. Gallows is the muscle, sure, but he's also more of a right-hand man. Punk could unleash Kaval on opponents, and then call him off when he's satisfied. His look fits the group, and you could believe he fits their lifestyle because of his intense training, strength of will, purity of a warrior etc etc etc.
This could still happen. We all heard the rumours that Ki would debut as someone from Rey's past, and shortly thereafter Punk began a feud with him, leading many to believe he would bring him in to get the 'Edge' on Mysterio. But then Gallows became more prominent and Mercury was cast as his masked helper, and the WWE seem to believe 3 is the new magic number in terms of stables, or 3 and a manager, and that would be Serena. Gallows and Mercury could form a team, Punk could go for the main event, and Ki could challenge in the mid-card. But I just have a gut-feeling this group will get no bigger than it is now.
They seemed to leave him off NXT in a very deliberate fashion. It suggested they have some specific plans for him. Perhaps they feel he can just debut as-is and get over. I mean the criticism of the 8 rookies was that they didn't really have much personality, and it seems NXT has been nothing more than a multi-week vehicle to showcase them and try and force a connection with the audience. It came to Danielson almost immediately, so he no longer needed the leg-up the show provides, and was booted, or at least that's my take on it. I think they feel the same about Low Ki, that he can just debut and get over.
So baring those two things in mind, I think he'll end up just appearing randomly and attacking someone... or win some squashes. I think he'll appear on Smackdown, and I think he'll dominate the mid-card and if it goes well, he may even flirt with the main event. I don't think he'll achieve Punk's level of success, because I think he's the gold standard of former indie talents, but I think he can do well for himself.
The only thing I think that might hold him back is he is injury prone. He's had quite a few in his career, including at least two major ones to his legs (I think). He's out of action as we speak because of injury. Mr. Kennedy/Anderson's career hit an unmistakable speed-bump because of his frequent injuries, and this could happen to Ki as well.
Finally, his ring-style. I was sure they'd force him to tone down his stiffness. I never imagined he'd be allowed to do the Warrior's Way/Ghetto Stomp. I thought he'd become frustrated at not being allowed to kick at full-strength. But I've watched footage and give or take a little, he's the same old Ki, murdering fools and showing no remorse doing it. His finisher is the same, his stiffness is the same, he's still Low Ki. So basically, a problem many thought he'd face, is not a problem.
If he can stay healthy, I think he's golden.
