I used to give many different combination of raw/canned/kibble! I'd keep the same kibble as a base and do add-ins like Stella & Chewys/Nature's Variety or some type of canned food. I'm not currently doing that since we are trying to lose weight... it's easier to keep track of calories if I just feed one type of kibble with maybe some canned pumpkin or a single canned food
I think the only downside is if something doesn't agree with your pup then you may have trouble pinpointing which food/ingredient is the culprit. But if your dogs are thriving on this feeding schedule and having no issues, I'd go for it!