Regarding Bard swarm kiting (I got to 55 before quitting).
You actually cast your AoE dots which have a very small range advantage over the melee range of NPCs. EX: Your lvl 2 and 18 dot have a range of 17, mob melee range is 15. The level 18 dot has a slightly bigger advantage, so most people typically end up only using that for damage, as using the level 2 dot requires you to be extremely close to the swarm. To achieve this by yourself you need to run a sort of oval shaped pattern, swinging in close right as the dot is about to cast, hitting the entire pack and swinging back you.
You never use AoE snare while solo kiting. The AOE snare is used typically to power level people, as it has huge agro, and allows a high level bard to keep a nice tight pack for lower level guys to cast PBAOEs to hit everything.
After mid 40s, when you hit the dreadlands, the Melee range of the mobs is even closer to the range of your dots, so you typically see two people AoE kiting packs using low hp agro. (Supposedly this was nerfed since I played last) That involved a bard getting down to sub 20% health which was basically ironclad agro on your pack. With higher hp mobs however, the second kiter doing damage would need to log out to clear agro (even with low hp agro, the mobs in dreadlands, burning woods, etc. will eventually turn onto the bard doing damage because their health pools were so large). One logout sufficed in Dreadlands, 2-3 times were needed for Burning Woods mobs. Any class that has access to a move speed buff could be the low hp kiter, however, bard speed was required if you wanted to kite caster mobs, as they were able to stay far enough ahead of the mobs so they wouldn't be constantly stopping to cast spells.
After the 40s, it's not really viable IMO w/o a partner. It just takes too long to kill things, and one mistake during an hour long circle running marathon costs you all progress.