The right mix
I watched some of the 2003 and 2015 RWC games tonight. One thing that stood out to me A LOT was 1. The size of the wings which were very effective (lotte and Del) 2. The work rate, kicking ability, and importance of #12 (Elton) 3. The work rate of 7 in tackling and jackling which was WAY higher than our best 7s now (Waugh) 4. We had an added flanker in our prop (bill young).
To watch the old games versus our game now was honestly refreshing. Adding all these things takes pressure off the 10 too.