I have noticed their has been a gradual decrease in popularity for vertical loops to be implemented on roller coasters over the past 10 years. This is especially true for any ride that Rocky Mountain Construction has built (or ever will build), and it's looking like they will be the dominant coaster designers of this generation. Loops are just too much of a double edged sword. On one end, half of the GP thinks it makes the ride 100x better and fun. The other half is too intimidated just by the thought of going upside down, let alone through a fast high-g loop! It makes sense from a business perspective to keep inversions as a series of twists, barrel rolls and overbanks, since it doesn't alienate half of the park's potential guests. I think the vertical loop will one day be viewed as an archaic roller coaster element of the past, although it would be fun to ride a coaster with a vertical loop every once in a while, similar to riding old 20's wooden coasters nowadays.
I mean just look at this
and this
and this
compared to this
and this
and this
I see RMC's style of implementing inversions and overbanks dominating the industry very soon, leaving the traditional loop as a part of roller coaster history.
And if you don't think loops are going away any time soon, at least we can agree that OTSR's are! Right?