Hotspots should be PKing zones.
So what about adding pirate hut and axe hut to hotspots? They're great xp, maybe it would give trainers incentive to hit the HS up. I know both of those are close by. I would say mage bank, but no monsters there. Hob mine maybe? Maybe not lvl 30 greens, as castle already is one.
So...
Castle we know gets a lot of attention and can be a pain to hold.
Red drags, not so much attention.
Edge dungeon, can be annoying.
Ice plateau, used to be a hot training spot.
Graveyard definitely is.
Bandits, maybe. It can be, but isn't really a training spot.
Not to say all have to be the "hot" training spots.
Sometimes it says they change to another spot, but they don't it seems like.