1.Pre: If this is only for ABD then that means two thiings in my mind: It's eaither a slippery slope segway or a waste of time and resources.

1.1. I don't really see how players being able to start, effectively one turn or so into the game, increases gameplay possibilities or uniqueness. Gameplay possibilities maybe. Uniqueness? Not at all. The only way you'll achieve uniqueness in stances if you let people create their own like flames.

1.2, 1.3, 1.4. Contextual replies.

1.5. Yes and no. Depends what sort of advantage this will give. And don't say it won't give an advantage because it'd be near impossible to balance and there's no purchase incentive if there's no advantage.

1.6. See point 5.

1.7. See point 6.

1.8. See points 5, 6 and 7.

So now initially we can see that a lot of this will hinge on if/what sort of advantage it will give (see point 5) and how it might be implemented (see point 1).

2.1 Are new starting positions not gameplay altering features? In part 1.1 of your arguments you say "New stances widen the gameplay possibilities".

2.2 Fair point. I am not especially active ingame either but I have enough knowledge about ingame and the wider Toribash community from my years here and in community management to have a fair grasp of the topic at hand.

2.3 Just because he supports the idea doesn't make it a good one.

Discussing userbase. Goody.
Now I don't have access to the analytics that you do so take all of this with a grain of salt.

Point 3.1: Black market. Wtf? Answered in part 4.

Point 3.2: 15k subscribers != 15k people watching your vids.

Point 3.3: This could bring more users in the same way any change has a chance to bring more users. Honestly though I really don't think you'll see any marked increase in adding this one feature (even the 'steam population boom' numbers are/were very underwhelming).

Point 3.4: One user's opinion doesn't justify or cancel an idea (and I appreciate the irony of me saying that here in my post but you'll note that the great majority of users here share my opinions on the idea).

Point 3.5: I am appreciative of Nabi/hampa's efforts and proactivity to spice up the game going forward but I ask that you listen to your users and think carefully about these changes. (Wouldn't hurt to put the admins in the loop either since we do really know the community better than anyone else but that's another case entirely)

4.1. Now I'm seriously starting to question your intelligence, no offense.
User/user tc selling is "the black market"? News to me ( and I'm the head of the msquad :s)
Too much trouble. Ya think? Although if you were interested in entertaining the idea you could feel free to chat to me/the squad any time about feasibility and runnon effect.
Other solution off the top of ym head for example: Fixing the $/tc prices in the shop - talk to sir about that one since last I checked he was the "marketing guy" for Nabi.

4.2. If you can get it to the point of balance so that it is merely a matter of preference then I will eat a hat and film it. This is one of the main points that all of this revolves around as I said in part 1.

Thanks for reading this far.

The main points to take away:
Will it/can it be truly balanced to the point that stances become merely a matter of preference or a customisation point.
If it can be balanced to the point that it's just a matter of preference/style then I don't have a problem. Quite unlikely that that is possible though.
Another idea if a change in gameplay is what is being looked for: Mod/gamemode/rooms where both players start in new position. Tada, no balance needed.
If it will add any sort of advantage or similar then get the fuck out.

Additional thought points include: How will it be implemented, how will they be created, how will they be balanced, how much will they cost, is it worth it to have it implemented in just ABD, is it worth the effort to implement it in other mods then, is it worth doing at all or are the time and resources better spent elsewhere.