I think that it caught everyone by surprise when we started playing it, but then teams adjusted and we never adjusted back to their adjustments. Two years ago the LBers were all hurt, last year the DBs were hurt, but we were told that we would be playing more four man fronts at the start of the year and really never did.The 3-3-5 was failing because we didn't have the dudes. The LB corps had more injuries than an Indonesian earthquake the past few years.
And even though the 3-3-5 helps hide not having a great DL, you still have to have at least 1 great or a couple good guys in the DL. The last 2-3 years there were a few guys but no dudes.
It just got old watching the QB have all day in the pocket to throw the ball, we had little to no pressure on him, putting even more pressure on the LB's and DB's. the positions we were already short at. How many times last year did we have someone running wide open down the field for a long pass and score on the defense, it seemed like one or two a game. With 5 DBs in the game that should never happen, no matter what their experience level is.