Castrum Meridianum is ruined.

[Blanchimont]

Except it is just ARR. HW doesn't have nearly as many filler quests as ARR does.

It doesn't matter if its filler or not. The daunting task of having to complete 500+ MSQs in order to enjoy the end game content is way too much to ask of new players. Here's a game, but you have to do 40+ hrs of quests first.

I don't think going through the MSQ is a problem. I call it playing the game - the fun part of the game.
Eventually you run out of quests and reach the end of the game which seems to consist mostly of running boring dungeons over and over and over again.

It was fun in the beginning, but the more you have the more tedious it becomes and the bigger the barrier to entry becomes and it will only get harder to find people to do dungeons with you as well as players are scattered across a larger and larger area. The 500 quests will easily take someone over two months to do. That is two months they have to invest before they can even get a chance at the end game provided they manage to reach that point at the beginning of a new equipment cycle.