My clubmaking knowledge is limited. Two things I know though: 1) Switching from graphite to steel will change the swingweight of the clubs (that's the felt weight of the head while swinging). 2) A stiff, steel shaft will increase your accuracy (in both directions - if you swing bad, it's going to show up even more), and reduce the distance compared to the graphite.
If I decided to do it, I'd definitely have a certified club maker fit the clubs to me while I was at it.