I'm sorry to hear that about the high level roulette being so unfriendly toward new players: unfortunately a lot of people don't understand that those old dungeons used to be more relevant back then and on top of that players had more time to unlock them. They weren't 15 at the beginning!

And really, not all of them are really that fun: besides Wanderer's Palace NM, Brayflox HM, Amdapor Keep pre-nerf and maybe Pharos and Copperbell HM pre-nerf, the others weren't that great nor different: trash->run corridor->do boss->repeat. This is personal opinion but having 15 dungeons to catch up, while it's quite a lot, doesn't always mean they're good and WP HM, one of the last 3 dungeons before expansion, was probably one of my most hated dungeons of all (gotta love those long, pointless corridors).

As always, Quantity ≠ Quality.