Here are 3 (long term) suggestions, which could help the gathering classes being more important, interesting and fun.
Introduction
I think it would be great if gatherers would get rare and exciting items they can look forward to obtain. The feeling would be similar to the FFXI NM itemhunt, where you need days or weeks to obtain one single item, but the big difference would be, that the time is not lost. You would get it through your usual gathering routine or by (which is a lot more fun ^^) adventuring/travelling.
So the basic idea is to give gathering classes additionally the same type of loot that DoW and DoM classes get.
It is somewhat strange that you need a fighting class to gather the most important materials for your high level gear. I'm talking about your Ahriman Wings, Mosshorn Scales and Great Buffalo Horns.
So the first idea is:
1. Give Gatheres some exclusive items, for high rank gear.
I think of specific spots, which randomly appear or simply usual spots where you can obtain gathering-exclusive material (with a small percentage of course).
For Example:
Miners could get (with a little luck and time) a rare Ore, which can be crafted into a unique Cuirass.
Botanists could get a rare wood, which can be crafted into a unique Bow.
2. Treasure Chests with Equipment and Gil
Think of it like that. Someone stole money and hid it in a rock. Someone crafted a unique gear and hid it in a three.
You would get the chance (of course with a reasonable chance) to optain this kind of loot too.
It would also be a very good way to introduce Rare/Ex Gathering Equipment. For higher ranks, but also for middle range ranks. Why should fighting classes be the only one with sweat rare/ex gear. ?
3. Introducing special Gathering Locations
The Miners have already Mines. It would be great so see activitees to focus more on these. Well, because it simply makes more sense and you feel more like a real miner.
Gatherers could get special forests. Areas with lot of tress, where they also can feel more like a Botanist.
Introducing the rare loot can be a great motivation to visit these special locations.
Finishing Thoughts
I personally see great potential in the gathering classes. They could be a wonderful treasure hunting class, where you need to search the land, cross deserts, oceans and mountains, just to obtain the one single item you are looking for weeks.
This is my exiting vision of the future of gathering classes.