After using the new 515 now for nearly a month, I wanted to suggest a change that would bring this spell to a place of compromise. I believe the general consensus among the player base is that the cooldown should be removed because the addition of a 1 second RT was enough to lower the power of the spell. We're also seeing that 515 has a tendency to become unreliable when it falls at the wrong time in combat, essentially leaving a wizard in a tight spot, especially against powerful capped foes. Even at 3x harness and 2x EMC, I'm finding it very unattractive to activate 515 during the cooldown. The added mana penality is definitely effective in making you not want to do it.
I agree that removing the air lore benefit of occasionally casting a spell at zero RT was the right thing to do. It only encouraged mindless keyboard spamming. However, the new air lore benefit of occasionally channeling a spell is unfortunately even worse in my opinion. Currently, I'm not even seeing real hard evidence that channeling bolts is something I'm ever going to want to do. Maybe it's just decades of never being in hard RT that I need to let go of, but I'm also not seeing the results of channeling that I think most of us would want to see. The true downfall of channeling though, is that is basically has zero effect against non critable foes. Too many critters are immune to being crit killed for channeling to ever be a staple in capped hunting. I have to admit that it hurts hunting the confluence and seeing rapidfire's zero second channel flaring, and knowing that it isn't helping me at all.
What I would suggest to balance some of the concerns of 515 is removing the channel perk and adding something like this.
Training in Elemental Lore, Air has a seed 5 summation chance of renewing rapidfire for (seed 10 summation/2(rounded down))seconds on every cast of a spell.
Example a wizard with 35 air lore ranks has a 05% chance of renewing rapidfire for 1 second
Example a wizard with 108 air lore ranks has a 10% chance of renewing rapidfire for 4 seconds
Example a wizard with 202 air lore ranks has a 16% chance of renewing rapidfire for 6 seconds
Lets use the example of a wizard with 108 air lore ranks. Lets say they are standing in the middle of a large swarm where targets were not an issue. If they cast 60 spells in the 60 seconds of rapidfire, which honestly isn't happening, but lets just say they did, they would see, on average over time, rapidfire flaring 6 times, adding a total of 24 seconds to the length of the spell. In that additional 24 seconds, rapidfire will flare another 2 times, adding 8 seconds, and then possibly once more again, adding 4 seconds, for a total of 36 seconds to rapidfire's length on average. You would only see the addition of 36 seconds if you were standing in that huge swarm, casting a spell once a second on the second. This would be hugely beneficial in keeping rapidfire from falling during a swarm, when you really don't want the spell to fall. However, the second the swarm is finished, by the time you pick up your treasure and head out to find more critters, your added time to rapidfire will expire and you'll be on cooldown, just like normal. Effective when surrounded with targets and at your most vulnerable, less so when facing a critter at a time and moving around a hunting ground.
Isle Snack Muncher