They listen to many things, that doesn't mean they act on everything. If there was going to be a harder difficulty mode added, they would have mentioned that in one of the recent updates.
Because they have not, that means there won't be one when the DE releases. That does not rule out the chance that they might add a harder mode to the DE some time after release, but it does make it less likely.
And honestly there is such a wide variety of player skill that finding a harder difficulty which would be good enough would be difficult. You have people who complain that Explorer was still too hard, and at the other end of the spectrum you have Qiox who boasts that he beats honor difficulty without using any magic schools or any healing except food.
