1200 is a big number in terms of offensive stats stabilizing. Plus you have to apply a haircut to his minor league numbers to get their major league equivalents. I wouldn't completely discount his ML numbers. But in trying to project his 2016 performance I would give one-third weight to what he did in the majors last year, one third to what he did in AAA last year (with the appropriate haircut), and one third to what he did in AAA in 2014 (again with the haircut).
Just using simple rudimentary math here, but if you use ~600 ABs as a full major league season and use his most recent performance since it should be more reflective of power typically being the last tool to develop, why would you discount his numbers so harshly?
He hit 22 HRs between 2014-2015 at the AAA and MLB levels in 864 ABs, with his output increasing yearly.
Players with .155 ISO or lower last season:
Derek Norris - .153, 14 HRs
Buster Posey - .153, 19 HRs
Ian Desmond - .151, 19 HRs
Jason Kipnis - .149, 9 HRs
Brett Lawrie - .148, 16 HRs
Marcus Semien - .147, 15 HRs
Addison Russell - .147, 13 HRs
Jason Heyward - .146, 13 HRs
Jose Altuve - .146, 15 HRs
Don't get me wrong, I'm not expecting bigger things than anyone else is. That said, I don't see why it would be out of the realm of possibility that he provides at least 15-20 HRs given that he's been trending upward with more plate appearances over the last couple of seasons. Even Steamer projects him at .132 with 12 HRs. One could argue that he's at least an upgrade over CJ in the power department - not that that means much, of course.
(BTW (and only to get a rise out of folks), that actually is the same Jose Altuve you think that is with the same ISO and more HRs than Heyward last season.)