That actually sounds like a really interesting idea. Not just one storyline, but two different storylines, depending on which side of the law your character decides to be... I'd love seeing something like that, but then, I always love seeing plotlines where choices actually matter! Even if it means one needs several characters to see all the options.*sigh*
How difficult would it be to implement alternative questlines in this, where when you arrive in the zones you get the choice to allow yourself to be recruited into the respective guilds, or you alternatively can be informed that they are a problem in the region and you can take on an enforcer role to try to drive them out?
Eh, idk, I'm not against them making alternatives for good guys but I hope it still has consequences. If you can be good and reap all the rewards from being bad, without being bad, it cheapens the whole thing. I like things like the choice at the end of the Mage's guild quest line, choosing the good option means you miss out on some skill points that can't be gained any other way, being bad means you get them. It was a good test to see if your character is really good, or just a mercenary pretending to be good, up until being bad is the only lucrative option.
I agree with this, and also with the "good character" RP point in the OP. In both Oblivion and Skyrim (the only games where you could join the Dark Brotherhood), there have also been options to actively not do the Dark Brotherhood questline, which both start with you killing the recruiter. In Oblivion that was it, but in Skyrim that led to an alternate questline where you wiped out the Dark Brotherhood in that region. I'm hoping ZOS keep this design setup for the Dark Brotherhood in ESO, so that we can go to the Gold Coast and help remove the Dark Brotherhood from the area.*sigh*
How difficult would it be to implement alternative questlines in this, where when you arrive in the zones you get the choice to allow yourself to be recruited into the respective guilds, or you alternatively can be informed that they are a problem in the region and you can take on an enforcer role to try to drive them out?