tldr; Farming in itself is not an exploit if the rewards aren’t providing you an unfair advantage over others. Safe-spotting is an exploit, as it provides an unfair advantage. AFK abuse is a party that is farming is also an exploit.
Long post inbound. If you want to respond to debate my opinions, please take the time to read the words below.
Exploits are defined as abusing a system by using it in an unintended way, specifically to gain an unfair advantage. If you want to find out if something is an exploit or just a system that needs to be rebalanced, break the topic in question down in to parts that you can define as being an unfair advantage and an unintended use.
Pastor Walsh was the only one mentioned in the current patch. Why? Possibly due to his loot table, or due to it interfering with quest progression due to so many players being in the area. Either way, it was decent for weapon masteries when your level was close to his, but after you are too high leveled, it is barely a dent in XP or Weapon Mastery.
Lodestone Bears - There are originally three in a wide area, allowing for a good path for a solo player to farm bears for skinning, several materials for Gathering, lots of iron for Mining, and honey/mature trees galore. The bear in the cave is the one in question of being exploited. What happens? Each new player in the area increases it’s spawn rate. After 6 players are in the area, suddenly new bears start appearing before the previous bear is even killed. If you are in the level 20-30 range, this can be effective for xp/weapon xp, but your skinning level has to be high enough to skin the enemies + you have to survive the endless assault of bears to be able to skin them. I finally saw one of these farming parties last night on my server and hopped in at level 38. Result? 18 XP/15 weapon XP per kill. So as someone already leveled, this was not worth the time or effort since the bears loot table is atrocious, it consumes food/potions, and durability loss costs from getting slapped constantly. Not to mention it was impossible to consistently skin bears do to 3 bears running around doing AoE attacks and other players skinning while you have aggro.
So is Lodestone Bears an exploit? I say no. The window of “exploiting” it is limited to certain levels to be effective by any means, and skinning is already the easiest 200 that you can achieve by simply skinning enemies you kill. After you are able to skin 40+ cat-type beasts, you will hit 200 way before you reach level 60. The loot table is also nothing to write home about.
What about the Boar farm? Not even gonna expand on this one as much, but it is a higher level area, so it is limited to well-geared adventurers… under normal circumstances. If anything could be considered an exploit in this area, it would be the ease of safe-spotting huge groups of boars. Safespotting and mass-AoE removes all risk of this farming method, so everything is just a gain/reward. The spawning itself isn’t really an issue, the lack of risk is. Remove the tents/other objects that prevent the boars from fighting back and problem solved, risk is reintroduced and there is a cost that comes with participating in this farm.