Hi everyone. Sorry that it has taken me so long to reply to this topic and come to a decision. As I'm sure you can all understand, deciding the fate of a Pokemon isn't something to be taken lightly. I've discussed my thoughts and listened to the thoughts of many individuals in this thread and on Showdown about Talonflame and the effects that it has on the metagame, and based on these things as well as my practical experience both using and facing it, I've come to a decision.
Let me preface this by saying that I realize no matchup, no matter how lopsided, is completely un-winnable. There are very strategic ways to overcome poor matchups, and that's one of the things that makes the Monotype metagame so exciting. The second that Mono-Dark is faced against Mono-Fighting, you know who is going to be favored to win, but it's still a matchup where either side can come out on top. The problem with Talonflame is that it takes already very lopsided matchups (Flying/Fire v. Bug/Grass) and makes them almost 100% guaranteed to end up in the Talonflame user's favor, and it takes another matchup (Fire v. Fighting) that should be fairly even and makes it considerably more lopsided for the Talonflame user.
Again, I realize that Talonflame doesn't mean that you auto-win in those particular matchups, and I understand that each of these types has its own way of beating it. As I pointed out earlier on in this thread, Mono-Grass can utilize Rocky Helmet Ferrothorn to rack up an insane amount of residual damage against Talonflame without even attacking it. But then what do you do against Swords Dance/Roost Talonflame? And then what do you do when you need to use Ferrothorn against something else before Talonflame even comes out? Most of the time, you simply lose. There is no surefire way to beat this one Pokemon on any of these team archetypes because, unlike other Pokemon in other matchups, you can't just run priority and hope for the best or run a Choice Scarf user and revenge kill it. A 120 Base Power STAB priority move with amazing neutral coverage is really good in standard OU, but when you go into a Monotype environment, some types have no reliable way of defending themselves against it.
Basically, without Talonflame in the metagame, Mono-Bug, Mono-Grass, and to an extent Mono-Fighting have more room to grow and prosper, while Mono-Flying will still be a fantastic type because of all of its amazing options and Mono-Fire will still be totally usable, particularly so if a lack of Talonflame causes Mono-Bug and Mono-Grass to rise in popularity. In order to promote more diversity in the metagame, Talonflame will be banned from OU Monotype.
Now that all of that is out of the way, I want to talk very briefly about suspects and bans in Monotype. If I feel uncomfortable making a decision on a certain suspect because I just don't know it well enough or I simply cannot come to a decision about it on my own, I will hold a vote with a council of users that I will determine sometime before the vote based on quality posts in this thread and knowledge and experience in the metagame as observed from the Showdown Monotype chat/Showdown ladder score. This is something that I'd like to reserve for very special circumstances. Holding an actual suspect test would simply be too difficult, particularly because this is an unofficial metagame, and a suspect ladder wouldn't see enough activity to be worthwhile.
For now, I'm interested in hearing your thoughts on what the metagame will look like without Talonflame. How do you think Mono-Flying will do without it? Do you think this will give Mono-Bug, -Grass, and -Fighting some room to grow? Will the hit from Mono-Fire indirectly affect the other types? Let me know what you're thinking. Also feel free to post replays of your teams in this thread so that we can see the metagame in action! Please limit discussion on whether or not you thought the ban itself should have happened; I've had the chance to hear your opinions, and a decision has been made.
The ban should be on the PS server as soon as possible. Thanks everyone!