It just came in my mind, that i would be really happy, if we could get collector's editon bonuses, if we pre order trough steam, but of course, in form of downloading it. I'm a huge fan of walking dead everything (comics, game, series), but i would rathet stick with buying on steam, because i bought S1 on it, and i prefer to have my games at one place, also, y'know, achievements, cards, nad stuff! :) It could be like with Alan Wake, which has a Collector's Editions extras. It contains literally the stuff you could get trough shipping, but in downloadable form.
I'm not sure if they would do it, but i would be a really great fan of it! :) Have a good day!