Hey I enjoyed that you did one and almost all of these mock drafts end up being just dead wrong. No hate towards you, I just have seen this play out a bunch and I just know how they feel about rb's and qb's first round. You can go on a run of QB's sometimes depending on if there is a run early on them but I don't see any of these QB's being a standout, sure- fire, franchise quarterback. I would expect a max of 2 in the first round because you can get a Kelly type player in the 3rd or 4th who is a great value with experience.
As far as running backs, remember Mark Ingram went at 22, Henry went mid second round, Ezekiel Elliot was the only first rounder last year and and all three of these guys are thought of better than Dalvin Cook. Fournette will go as he is a special specimen but might not go as early as you think. These teams don't want to pay all that up front money for a position with a 3 year life expectency when they can get value in rounds 2 or 3.
Big, fast athletic linemen and players on the outside with ball skills are much more rare than guys that can tote the rock for the 3 yards. This is why you will see 6 O-linemen, 6-8 Dlinemen, 3 or 4 linebackers, 4 or 5 wide receivers, 3 Corner backs, 3 safeties, 1 or 2 Qb's and 1 or 2 rbs. it's been pretty consistent