1) Removal of dependency of TH: Having TH is nice, but it should be a bonus, not a requirement for anything. When drops are so crappy it's almost manatory to have TH, you're introducing an element that ends up hurting the overall enjoyment. Drop rate of all items should be raised to "TH2" drop rate and TH in general should be a +1% increased chance of drop per additional level. This make for an across-the-board increase for everyone, not punish TH jobs, and pretty much make everything slightly more available to everyone.
2) Removal of obnoxious repop timers: When it only takes 2 people to overcrowd a popular camping area, there's a problem. Especially when it's an area with a time limit that has a very desirable drop. EVERY standard monster in the game should have an initial 1 minute repop timer. After the monster is killed the 2nd time, it's reduced to 45 seconds, then 30, then 15, then 5. This repop time would maintain until the monster is left alone for 10 minutes, at which time it resets to the default 1 minute. This would allow for individuals and groups to sustain with one or two monsters for the entirety of their camping time, instantly allowing every camp in the game to handle 5x as many people/groups.
3) Dev team realization that this is a game. Games are meant to entertain. You aren't damaging FFXI by making jobs more powerful. There is so much content already that even if things took 1/5 the time that they currently do, this game could keep a player busy for years. Rather than bothering with toning down jobs, simply read over system parses and slowly increase the damage and capability of the jobs that consistently fall behind. Obviously no one needs to be overly powerful to the point where you steamroll everything, but that isn't really the case at the moment even for the most powerful of jobs.
You have the right idea with adding new content to old zones, but consider making some of the most desirable items attainable from multiple sources (with appropriate drop %s) to allow players to experience a variety of content to achieve their goals.
We aren't in Vanadiel to work. We're there to have fun.