Yeah, you're right. Cover 2 can be strong deep coverage if it's also man coverage underneath. I was more thinking of plain zone cover 2's which are just terrible against deep routes. I work mostly in zones for my straight out pass coverage because we seem more likely to get picks that way... probably also stems from having to work with very weak talent in my secondary when I started my dynasty... the zones worked best so I never bothered to stray far from it. I don't know how it would work now with my strong secondary (3 of 4 starting DB's are in the Thorpe award list), but I also use to have trouble getting beat medium range to the middle in man defenses like cover 2 man. But man coverage underneath does do better than zone against some out routes and passes to the flats. I should try experimenting and mixing it up a little more.
I know in real life when teams try to run the cover 2's against my Warriors though, they can really eat you up deep!