I will be the first one in line to have a litter.
Seriously reading threads about this game's PC release I've definitely noticed a few people who seem to think they are getting into an Elder Scrolls-like experience. Gameplay-affecting mods would totally defeat the purpose even if they weren't used to cheat or grief people online (and they will, if it can happen on Xbox it can definitely happen here).
Even if you just played offline in your own little sandbox...you're missing a big part of the game. I don't personally do this but I can kind of understand why someone would play Skyrim and mod his character to have the Badass Looking Armor of Invincibility with a flaming sword that instakills everything right from the get go. Make your own fun, and all that. But to me the Souls games are not an individual experience both inside and out. I don't want to go into a thread, see someone relating his personal horror story of curse frogs in the depths, and then see people say 'oh just download xX420sniperXx's no cursefrog mod, it totally improves the game'. Obviously a silly example but it's just my line of thinking. Even if there were mods in the vein of super-hard romhacks I still don't think it'd be worth giving up the online functionality unless they got popular enough to develop their own community following.
But whatever, enough speculation. Who knows what'll happen, maybe the port will be so bad that we'll need mods to save us, or maybe there will be rigid anti-cheat measures that somehow weren't in place in the console versions.