With a good boom vang, outhaul and cunningham I found that the original style traveler worked well enough to leave in place. I sailed my 1980 C22 alot, in big wind and I sailed her hard. Changing to a different system will prevent your being able to race in 1 design races or with a standard C22 rating in other races.
I did go to a "loose footed" fully battened mainsail and the boat really stepped up in performance.
The C22 is really one of the most rewarding boats to sail if one learns to use the many different controls they came with and will just about whip up on any other boats in their size range.
I sold my boat last summer and went to a '82 San Juan 23 simply for the additional room in the cabin. This allows my wife to sail with me again as the C22's size hampered our ability to take our week long trips. Old age and infirmities require some trade-offs.
Enjoy your 22, they are great boats.
Ray