I've reveged several different strains with mixed results. I think that different strains have different tolerances for the trama that you are putting them through, kind of like some will clone easy and others won't. That said; the first thing I would do is to re-pot. I trimmed my root system down to around 1/2 to 1/3 of original size and re-potted ( I used ocean forest ) I then fed with a high N fertilizer, as nitrogen has pretty much been depleated from a mature plant. Then I kept feeding with grow ferts. A little bone and blood meal in the soil when you re-pot would also be a good idea. When the new growth starts, it will look a little strange, twisty leaves, single leaves, etc. Not to worry as this is normal.
On a side note, I am currently trying to re-veg a Power Plant that I grew last season and didn't have the forsite to gather some clones as I should have. This particular re-veg is different than the others as I am trying to do it just with the root mass and stump. The reason I think this might work is that when I harvested my crop a year ago, I just dumped the root balls into the compost pile. About a month later I saw several dozen babies starting out of the mass. I didn't persue it at the time as I had too many going plants and didn't want to mess with it. But I did remember it. I am also re-veging a cherry deisel that I grew out last season. It's too early to tell wether it will be successful or not.
Re-vegging takes time and patience. Most people don't mess with it because of the space it takes up and the time it takes. Personally I like the idea and do it pretty regularly, as I don't always have a mother to take cuttings off of nore do I have the finances for seeds.