People seem really nervous that the ability to get party SP is gone since we assumedly can't spam the same dunes/rr/levin/(toads) over and over for easy spammage SP. If you look at the last letter from the producer about Yoshi's level grind strategy:
The ideal image is one where if you play every day for 2 hours or so, you will be able to reach the max cap on one class in about 3-4 months.
This about sums up the changes to leve's, as right now it takes 5-6 weeks to get from 1-50. And this is only playing for 2 hours 5 days a week.

There are many places to level but the sp is just no where near the speed we have been getting used to with the leve failers set. I think this change was way overdue. In the 20-30 range you can grind in that dungeon south of bentbranch tam tara? Supports 2-3 parties I would think. Some areas of coerthas would be good for mid range as well.

By spreading out the population forcing ppl who want to grind to search out and explore for party spots I see this as a mandatory change for FFXIV to succeed. Imagine a player starts a new game for the first time in Grid and finds the world empty why would he bother trying to find Ul dah if no one is logged in his starting city? If they do a good job with this company quests I could see this further spreading out the populations.