While we can see that indicators for low level quests could be useful in some circumstances, after some consideration it was decided that the implementation of a grey exclamation mark or similar would lead to an over abundance of symbols for the many players who still have a large number of lower level quests.

It was felt that, over all, this would cause too much confusion and clutter on players screens when they are at quest hubs.

Q u o t e:
And what about making that option toggleable?

That remains an option for the future, but we won't be adding that at this time.