Couldn't agree more on that!
Scattered across tyria there are some beautyfully crafted places hidden by invisible walls or solid doors, places that you can visit perhaps for just an instance and then renderd forever inaccessible wich saddens me, because you can see that the place is still there on the map
for example:
the apothecary in the village of shaemoor, or the basement of the house in garenhoff, the uzolan's hideout in kessex hills, the house near field of the fallen in lion's arch, the cerebro replica in caledon forest, joon's house or mai trin's appartament just like azur said
and theese are just the first places that comes to my mind... this shouldn't require much work, since the assets are already there
please, consider the idea 🙂