So how viable is ranged fighting, or would you say its a support activity?
Ranged weapon are very powerful compared to others branch. But there is different kind of ranged weapon in Ryzom, all of them don't suit all kind of activities.
Launcher and Auto-Launcher are the one that does the most dmg (with zone dmg) but you will need to have packers with you and craft your ammo often. They are mainly used in outpost wars.
While pistol/riffles (and bow-riffles) do much less dmg to only 1 target at a time. But you can hold more ammos on your backpack (which means you don't have to be with you). Also, they requires less materials to craft ammos.
You can use them in daily PvP (their range is a big plus) as well as in PvE (since you have a big range you can hunt some of the named bosses alone when you know how to use them correctly).
Considering the fact they are (to me at least) very powerful, their is a big downside that makes them not that popular: while figting and magic skill need to level up only one branch, ranged weapons require you to level up 3 branchs. With those weaposns you will need to craft your own ammo and to craft you need to harvest materials and to craft more powerful ammos you need to craft them in higher quality. So, you need to: master at least one harvesting branch -> you need to level up the crafting skill for the corresponding weapons -> you need to level up the ranged weapon skill as well.