I've never bothered fermenting, and nor have any of my friends. It is only recently that I have heard any mention of ammonia occurring in the drying process, and I personally doubt whether it has much effect on the finished product. This is only my opinion, I've read nothing definitive about it either way. Frankly, if you're regularly ingesting nicotine, traces of ammonia, if they exist, should be the least of your concerns,- and homegrown tobacco is a lot less dangerous than the commercial stuff.
So, fermentation, do it if you want to, you may like the flavour better, you may not, I don't think that it matters a damn' for health and safety. (I am, however, all for fermenting sugar in water and putting it through a still, I may be doing that later today)