It's been a couple years since they were bought out, so they may be trying to get away with cheaper ingredients. I too have noticed some differences
You might want to try Merrick Before Grain. My Jennie is the one eating Wellness, and about 2 months ago I started feeding about half her diet with the Merrick Before Grain. After about 6 weeks, I began to notice a marked improvement in energy level and coat quality.
I mean, I thought she was doing so great on the Wellness, but since adding the BG, well...there is a big difference. I like to feed a variety of foods, but I am going to phase the Wellness out to only once or twice a week I think.