Cover 5 is a good defense to run at the end of games when you are trying to protect a lead. It's also good against the deep passing game, so your example makes sense to me. It has its weaknesses, but they all do.
I don't think I mentioned this before and I apologize if I did. One of the best things defenses do is give a qb one look w/their coverage pre-snap and then change it post-snap. Over the years, you have probably noticed me talking about both pre-snap and post-snap reads by qbs. Pre-snap reads can really be improved by film study. Again, tendencies are a huge factor. However, post-snap reads are about processing speed. It's an entirely different animal and not many are really good at it.
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