Hmmm I think the arrows may ruin the immersion for some but on the other hand, do you really want to spend hours hunting down the "right person" to talk to? Keeping track of a huge list of characters by having ,say, a "Notification" list as you move into an area which contains "XYZ characters" might work yet... that seems to require a lot of work.
That is what journals are for, to keep trackof the people you must talk _back_ and as per new ones it is more inmersive to talk to all them and see if they have cool stories to tell you and discover they may need or not your help.... As I said, just a different icon or little marker, or differnt color in the names, one color for trainers, other for quest givers etc, would suffice to differenciate them, but a neon gigantic marker arrow is a NONONO!