The number of deep targets is not relevant to catch %. The percentage of a players targets that are deep is what is relevant.
Here's what you said:
"MVS ranked only 56th in catch percentage out 66 receivers with at least 10 deep targets (20 yards or more)."
If a guy has 10 deep targets out of 100 total targets with a 50% total catch rate while another guy has 20 deep targets on 50 total targets with a 50% total catch rate, that's apples vs. oranges. The higher the deep targets as
a percentage of total targets, the lower the expected catch rate. Stated another way, the shorter the routes a guy typically runs, the higher the catch percentage is expected to be which is why, for example, you see a lot of running backs with 75+% catch rates and low yards per catch, with the pattern continuing through TEs and possession receivers.
Now, if what you meant to say is MVS ranked 56th. in catch percentage on 20+ yard throws only, not 56th. in total catch percentage, then fine. But that's not what you said.
I do not disagree that MVS had difficulties with deep balls, and actually routes in general, but the stats as you stated them is not a way to support that.
Through week 9, before he was semi-benched, his catch rate vs. yards per catch was pretty decent as I noted in an earlier post. His spot play after that dragged down his catch rate. He finished the season dead last in total catch percentage among WRs with at least 50 targets, that is true. At the same time, he had the second highest depth of target, clearly a contributing factor.
Frankly, I don't think it was his deep throw performance that got him benched as much as messing up shorter routes, and Lazard vindicated that decision with a very high 3rd. down conversion rate.