You've got some convincing arguments and I even agree to most of them.
To make it fun, collecting shouldn't be easy, that's right, but it should be realistically possible. A price of $400 for a little ABS fig is in my opinion bare every commensurability. I'd gladly pay a price of even $100 for a minifig which is very rare, even though this is also a very high price. But $400 (or, like last year, in Azog's case, $1,000) is too much even for a hard working man with no other costly hobbies.
And this is not just about collecting. LEGO is a building toy. I love building and sharing MOCs and it saddens me that (especially in the case of superheroes) I can't build all the MOCs I'd like to, only because I can't afford to buy the minifigs.
If SDCC minifigs are just variants of already existing minifigs (like Spider-Man for example) it is still okay, since I can use one of the regular Spidey figs (though, as a collector, I'd still like to have the exclusive, hehehe).
But exclusive figs like Bizarro of the Collector for example are in my opinion not really fair.
I'd prefer that TLG produces little exclusive sets without exclusive minifigs as giveaways or not to limit the exclusives to such a low number like 1,000 pieces worldwide.