No. Ring of wealth does not affect rune drops, it affects the rare drops (should you get a rare drop, ROW increases the chances of a higher valued rare drop) Fire giants suck, to be frank. They average 100-120k of drops per hour, and thats pretty pathetic. Instead of getting rune arrows, the ROW makes him get rune scimitars. Fire giants are excellent ranged training, with some cash bonus on the side. It just depends if you want more exp or more profit.