I recently switched my eleven cat household to predominantly wet food about a month ago.It did make a difference with my diabetic cat Nomad and it dropped his BG about fifty points.When I first tried this, I thought it would be more expensive but ironically it cost me less now.
I have not completely eliminated the dry food but I try to use it as only an occasional "back up" for my nondiabetic cats.I do use a grain free variety made by blue buffalo.
If you want some ideas on how to try feeding wet when you are gone for extended periods of time, see the post titled Holiday feeding from two days ago. Another reader suggested freezing canned so it unthaws gradually.