What should I keep in mind for storing wool roving? My wife recently went crazy for wet felting and bought a fair chunk of wool roving in a variety of colours. 

Likely it will take a while to get through it all and I want to be sure that it is still usable for a while. Currently it is just being stored in sealed plastic bags. They do not appear to be air tight. She did try to vacuum seal the bags, which I am not sure is good or bad, but since they are not air tight it didn't take. 

How can I store wool roving to maximize its shelf life in my home? I will assume there are considerations for temperature, humidity etc. 

I live in Southern Ontario Canada. I get dry winters and humid summers. While the house is regulated, in general, every nook and cranny is not e.g. basement, closets etc.
When it comes to wool, I think the biggest issue is moths. You don't want the wool to be eaten, so to store it somewhere where the moths cannot come, is a good idea to start with.
Then, constant moderate temperature and humidity sound like a good idea as you don't want the wool to dry out, become less soft, those kind of things. You're mentioning that the wool has a variety of colours, so I assume that it's painted and not all natural colours in different shades of white and brown? In that case, the wool grease has probably been removed, and drying out is less of a problem.
I myself have a lot of raw wool (including grease, dirt, pieces of grass and sometimes a dead beetle) for at least 10 years and I actually never did anything special to store it. The wool gets less greasy over time, but as long as there are no moths in the wool, you can do with it whatever you want.
(P.S.: Be aware that felt is a moth magnet!)