Look at the player we have in our system this year.

Fred Warner: a great covering OLB, who doesn't excel in pass rush.
Kafusi: perfect size for a 4-3 DE (no spot for him right now)
Stout: the prototypical MLB in the 4-3 (Taken out on certain plays)
Hinds: with a few more pounds a great 4-3 DE (no spot for him right now)
#62 and Johnson: are not NTs they are DTs

there are a few who fit better in the 3-4 like Taki Taki and past players like KVN, but there has been a lot of players who never had a place because of this like Jordan Pendleton. I really think the 4-3 is much more suitable for a slower more powerful team (White and Poly players).