Generally a Druid, but they can 'bug' out or do something suspicious due to their nature.
I.E. When picking a herb, if attacked, may sometimes try to keep herbing and not engage etc. -- with that, I wouldn't use them, but if I had some setting out of place, or if it's possible to overcome then sure, druids would be the best.
More information:
o If considering WoD gathering, via Flyer or not, then any class is really fine if you simply choose the building that enables 20% increased mount speed & a replication of the ability druids have to herb in form, but with any object.
o If considering gathering with a character close to the level of the mobs in the zone (I.E. 55-60 in Silithus or whatever), I'd recommend a Paladin or DK (Druid obviously if you can overcome the above somehow).
Additional information..
o For Druids, assuming you loot ~100 *NODES* of herbs per hour, you would only save roughly 2.5-3 minutes on re-summoning your mount (~ 4%<->5% of time per hour).
o Assuming you have the 10% speed bonus from guild or cloak, vs. the 20% (Non-WoD & Non-Garrison building gathering, and Artisan Riding) and assuming you spend roughly 50 minutes per hour on the flyer itself moving around... you would theoretically be 2.5% to 3.0% more efficient with the 20% bonus (Paladin/DK).
Summary..
1. Comparison
A. Artisan Riding & +10% buff... = 1.000
B. Druid with Artisan Flying & 10% buff... = 1.045 (If can fix druid problems)
C. Paladin/DK with Artisan Flying & 20% Buff... = 1.0275
* Choosing B over C, at best, the efficiency is only around 1.7% higher (Say that for every 500g you make per hour, you'd only gain an additional 8.5 Gold per hour)
2. There is no simple way to determine that any particular gathering benefit will be beneficial statically, but I just used them that way in this explanation because that's the easiest way to look at it, and is still relative over long periods of testing.
IMO, for Non-WoD gathering, choose a Druid if you know how to evade those problems stated above, or a DK/Paladin instead, with DK being a 'better' choice since they start at a higher level etc, however Singular has some issues with DK CR on AoE with low level mobs.
Also, for basic flying training.. I just take it as a fact that Artisan riding is worthwhile regardless of time spent botting. As for Master Riding over Artisan Riding, that's up to you. It is worth noting that (with the previous statement of assuming the static relevance of the simple numbers) Master Riding with it's 30% additive speed increase, it is roughly 7% to 8% more efficient for gathering materials (In comparison as.. 420%/430% vs 390%/400%).
So, for Master Riding, if you were to make an average of let's say 2,000 Gold per hour, you *could* make an additional 150 Gold per hour based on the numbers stated and assumptions made.
With that, assuming you pay 4,000 Gold for the Master Riding training and the assumptions are correct, you would "Pay For Master Riding Training" after 27 Hours.
There you go, should be all the basic information you need.
Enjoy the wall of text mate.
