Opposed: In the past, i have seen this tried and not work; it creates an atmosphere under which arguments are encouraged to happen because there is persistent systematic acknowledgement of their existence. There is also a heap paradox problem in the definition of ‘long arguments’: any drawage of the line will most likely be arbitrary, and leaving it up to “administrative discretion” creates a hole through which those with administrative power are given infinite power. Enforcement of a law to move arguments would require administrative intervention, something not always possible and something which would upset the atmosphere of Apionet.
I don't think this policy would require "administrative intervention" or "law enforcement". It could be something as simple as this: at any time, anybody can request that a present train of discussion be moved to the other channel; the conversation is then moved. (Unless those involved in the discussion believe they have a particularly strong reason not to, in which case ideally we try to collectively come to a consensus, and failing that there is some fallback. The fallback could be "the conversation is moved by default" or "an admin decides" or "everyone present votes", or probably other things. This parenthetical aside is much longer than I thought it would be.) There are various trivial variations that could be made to this, for instance requiring two people to request a conversation move, or something.
Anyway, this is all not important. My point is that a) drawing a solid well-defined line to define "long argument" is not needed or wanted, because this decision can be made on a case-by-case basis by whichever users are present; b) administrative intervention will not be necessary except, possibly, in extreme cases.
I propose we create a second channel, with a policy similar to what I have described, on a trial basis, for a period of say 2 weeks. After that, we can discuss its efficacy. If it isn't working, we can unimplement it again.