Personally I think the UltraSmurfs Movie was a PR disaster for Black legion ...they were (unfortunately) portrayed as inept Star Trek Red shirts.
actually.... its because of this thread i'm tempted to play black legion instead of iron warriors (my first choice). somehow it urks me that there are not "enough" of them, black legion marines. i mean... the lunar wolves/sons of horus way of fighting does look very ... eh.. "sexy". limited, but constant pressure through quick harrassment attacks and then an armoured, heavy deathblow to the command structure, "ripping out the throat". focus on tactical marines gives them flexibility and the ability to adapt, helpful for staying on the offensive. concentrated terminator speartips strike deep into the heart of the enemy (command structure), killing of vital logistics using a minimum amount of troops, freeing others up for constant pressuring harassment on other fronts, setting things up for new opportunities for heavy armoured speartips. after launch, if the black legion still is under represented, i think, i can warm up for a black legionnaire. with a bolter pistol in the left and a power fist in the right i'll champion the black crusade! ... i would miss the chant though... well the launch is not here yet, Iron within, Iron without!
Black Legion are kinda cool but they were the Warmaster's legion and he got a whupping. I know they became more since and they can call other chapters to their banner for the Black Crusades but in the chaos legions it's the most archetypal chapter which makes them uninteresting really. They're the big bad, big bad's are always a little cliché. In an action film the big bad is English, in horror films/games its usually something to do with a kid, in fantasy and fantasy scifi its some evil pukes that wear black. Snore. Well maybe not snore but it's hard to get passionate for something so basic even with other chapters being stereotypical(world eaters=zerkers, Word Bearers=Zealots, Thousand sons=wizards, night lords= terrorists and so on) they still manage it in a really interesting and engaging way. Black Legion do not. Just my opinion of course