I was curious about the numbers for the best mining class, so I did the math.
For my calculations I used 200 yards as the calculable distance between nodes and for I scaled speed from 100% run speed at 7 yards per second.
I didn't see fit to include any variables such as expectable obstacles, latency, command input/feedback delay or elevation changes.
The calculations are rounded to 2 decimal places, the mounting cast time and mining cast time has been added where relevant.
Keep in mind that the numbers may not be realistic, and I suck at math, but here's what I got:
280% Paladin/DK: 456% air
7*4.56 = 31.92 yards/second
200 yards in 6.26s
+1.50s = 7.76s
+3.20s = 10.96s overall per ore node
328.48 ore nodes per hour
310% Paladin/DK: 492% air
7*4.92 = 34.44 yards/second
200 yards in 5.80s
+1.50s = 7.30s
+3.20s = 10.5s overall per ore node
342.86 ore nodes per hour
280% Druid: 418% air
7*4.18 = 29.26 yards/second
200 yards in 6.84s
+0.00s =6.84s
+3.20s = 10.04s overall per ore node
358.57 ore nodes per hour
310% Druid: 451% air
7*4.51 = 31.57 yards/second
200 yards in 6.34s
+0.00s = 6.34s
+3.20s = 9.54s overall per ore node
377.36 ore nodes per hour
So if you are looking at a pure miner, by these numbers a druid could gather ~30 more nodes per hour than a Paladin/DK with their 20% mounted speed buff.
If you are looking to do both mining and herbalism on a character though, just throw these numbers out and make a druid, for obvious reasons.