Yep. Considering if you rush to 50, you'll miss:

1. The low level dungeon added quite a bit of people quit, and yes it is an actual dungeon (open world too.)
2. The subtle changes, especially to the UI which has changed the most between 2010-now, even if there's still a latency problem.
3. The tons of sidequests to do. These didn't exist at all in 2010 and there's actually quite a lot of them throughout all 3 cities.
4. The new class/job layout and so on.

There will/might be blood (I dont know this exact translation) for example is a very good sidequest for its level, lot a bit of story, decent fight involve, it's trivial to do at level 50 much like doing Ifrit (easy) as 50. Since anyone who played in 2010 and quit will not come back to the same game, it's UNPOSSIBLE to say otherwise.

That is what the campaign is for, not people who just quit when their free time ran out after they started charging.