I don't really know that leveling needs to be much faster per se. If you do it correctly you can get outrageous EXP. Leves/Behest could use more tweaking so that people can actually... you know... solo them. I don't quite know how Jobs are going to play out (if we get them the same level as the respective class or what) but it wouldn't be a bad idea to make the jobs start at lv1 and have a much steeper EXP curve. Have it so getting to 50 on a class is pretty easy but difficult to get a job to 50. Then have 2nd tier jobs that require 2 jobs to 50. (IE: DRK would be unlocked after getting WAR + BLM to 50). Probably won't be much like that but that's just my two cents.

With a huge volume of players likely to be dumped into the game at 2.0 launch I don't think leveling will be much of an issue. Right now its hard because everyone is 50 so a lower level player doesn't have much to party with but when 2/3 of the server is level 10-20 then it will be much easier. When the EXP camps are crowded by soloers, (competent) people team up together.