I'm not sure the walls of the Haven are really tall, thick or robust enough to serve as a firebreak against that kind of inferno, and the buildings within are kind of a flammable rat's nest. Any conflagration potent enough to do significant damage to the enemy army as a whole, all twenty thousand of them spread over a reasonably large area, is probably quite likely to be a dire threat to the Haven and the people trapped within as well. Bucket chains might mitigate that somewhat but: 1. organising that on short notice would be tricky and 2. even well-organised I'm unsure it would be a panacea against a blaze of that size just outside the walls.
A massive flame attack is very much either a holding tactic or an attempt to hurt them worse than we'll be hurt in turn, I think. Which is not to say that it necessarily compares terribly poorly to our other available options. I don't like sounding pessimistic in quests, but I'm not sure if there's actually a clean "win" option here. Which would honestly be very much thematically appropriate, for a messy, awful tragedy like the last great Kinslaying. It shouldn't necessarily be able to be averted cleanly or easily. Not that burning twenty thousand people most of whom aren't individually that bad would exactly be clean, of course.
I suppose I should do my due diligence and check further, though. @Sayle, just to have a rough idea, how much would it cost Figwit to say, rune a half-brick sized stone with an explosive force roughly equivalent to a Mk. 84 JDAM, and then send it seeking towards one of the sons of Fëanor? Or just their army in general, if we can't pick them out specifically? It's been long enough since Great is the Fall of Gondolin that I've kind of lost my sense of how much things cost, and also we didn't have Runes 5 back then.
If the answer to this question is like, "not that much lol" then I think that changes things significantly.
A massive flame attack is very much either a holding tactic or an attempt to hurt them worse than we'll be hurt in turn, I think. Which is not to say that it necessarily compares terribly poorly to our other available options. I don't like sounding pessimistic in quests, but I'm not sure if there's actually a clean "win" option here. Which would honestly be very much thematically appropriate, for a messy, awful tragedy like the last great Kinslaying. It shouldn't necessarily be able to be averted cleanly or easily. Not that burning twenty thousand people most of whom aren't individually that bad would exactly be clean, of course.
I suppose I should do my due diligence and check further, though. @Sayle, just to have a rough idea, how much would it cost Figwit to say, rune a half-brick sized stone with an explosive force roughly equivalent to a Mk. 84 JDAM, and then send it seeking towards one of the sons of Fëanor? Or just their army in general, if we can't pick them out specifically? It's been long enough since Great is the Fall of Gondolin that I've kind of lost my sense of how much things cost, and also we didn't have Runes 5 back then.
If the answer to this question is like, "not that much lol" then I think that changes things significantly.