You're right about the 4 years, it's too bad he doesn't have more time. I do see a lot of similarities between his game/contribution last season to Melvin's frosh/soph campaign. I don't think we'll see the leap that we saw from Melvin Jr to Sr year, but it'd be great if we consistently saw near double/double action Melvin gave his So/Jr years.
I actually see a leap from last year for Hogue. He was already as good of a rebounder as Melvin last year (both 8.4 rpg), so that should improve this year. And, his 3-pt shooting last year was comparable to Melvin's Junior season, and that should improve as well. (Melvin 2012-13:.348, Hogue 2013-14: .344.)
So, I think Hogue can step in quite effectively so there isn't too much of a drop off from Melvin's departure.
Hogue was still adapting from Juco last year so his ceiling for improvement is higher from last year to this year than Melvin's from his Junior to Senior years.