I'm just going to put this out there: Road to 70 ONLY applies through the first 90 days. You want to know why? Because if they don't want to buy the Story Skip and Level Skip, they have to Level through the game. And if they have to level through the game, then they need to do MSQ. If they have to do MSQ, they have to have appropriate levels. We're not even accounting for the Aetheryte Earring here, and it literally does a lot to help new players get up to speed in terms of Level with their friends.
In no way does Road to 70 ruin this game. You're still going at your own pace through MSQ(not telling anybody new to RUSH IT like you apparently assume new people are prone to do) and I literally told my friend who I gave a sub to to take the story AT HIS PACE. That's literally all that needs to be said. It doesn't matter if you're going 50 days or 80 days without doing anything in regards to MSQ or Leveling, it's still going to help push them through MSQ faster. The only hang-up right now if you're pushing MSQ is around Stormblood Lv 67, and that's still pretty close without Road to 70. Even so, THIS IS NOT A PUNISHMENT.
Also, let's read into your assumption about speedrunning this game, shall we? That community is literally 0.0001% of the playerbase, and is extremely minute in size. As far as people trying to speedrun the game, they probably just don't care about the story and want to get to content. WoW Players have been like that before, even the Refugees; but that's just stating some things I've seen with a fraction of that community in particular. A supermajority of people however will watch the story even with the buff on because they want to understand what's going on in said cutscene and the like, and how it leads into other things. If you're so afraid of a BUFF that helps new characters, then you do you Boo-Boo. I'm just stating the facts here, and speedrunning has not been a prevalent thing in XIV at all with new players just joining the game for the very first time.