Main Scenario Restriction Bloodstorm - Very Very Bad idea.

[Alberel]

People who dislike the grind to Heavensward or Bloodstorm aren't concerned over leveling. Plenty of these types would have that done within a few days. It's the MSQ itself they find tedious because you can't veer away from it. You must progress through the entirety to unlock the expansion(s).

Here's what I don't get though. The MSQs are an extremely fast and painless way to level your first job. The people wanting to rush to endgame would do so very effectively by simply rushing through the MSQs and skipping cutscenes if they wish to. Whether you like the story or simply want to rush to endgame the MSQ is still the best route for your first job with no armoury bonus. Having the option to skip the MSQ would result in these players taking much longer to reach endgame and thus defeating the entire reason they wanted to skip the MSQ. It makes no sense.

[Bourne_Endeavor]

-snip-

You'll easily outpace the story in terms of leveling nowadays. I had multiple crafts at 60 and Monk at 55 before I even unlocked Heavensward. And I didn't have the benefits of Hall of Novice or PotD to boost those EXP gains. While painless in a sense, it's still faster to spam PotD and fates than the MSQ because you can stay in one area and just grind. A skip potion would probably put someone at the lowest level that expansion allows too. The Chinese version put you at 50 since Heavensward quests require it.