All tobacco blends have additives in them, my man. :affraid:
Casings are added during the curing process for one, which are sweeteners and the like, sprayed on the leaves prior to and perhaps during the curing process. This is in essence universal. Then when blenders get the leaf they may or may not add their own solutions. Greg Peace wrote a good article about this, or at least commented on it in his blog. A quick google search might locate it. Many blends are advertised or at least described as "all natural" etc., and the tobaccos themselves are indeed natural...but the casings added to them are what they are...and they ARE present. I think that to find a tobacco without these additives (and believe me you wouldn't like it) you have to grow the product yourself, or get it from a grower prior to curing.
So take Prince Albert as an example...as basic a Burley blend as you're likely to find...sure there might be other blends out there that approximate it in terms of cut and flavor...but they too have additives...whether they are blended by GL Peace, Peterson, Cornell & Diehl, McClelland, Mac Baren, Peretti, McCranie, Pipeworks and Wilke, Gawith (both sides of the family), etc., etc., etc.
Honestly, I wouldn't worry much about the issue, as firstly you can't get away from it, and second, they only enhance the smokability of the blends. They won't hurt you...and have been a tradition for hundreds of years. The only one I'm not sure about is Tambolaka...and it's in a class by itself.
After that, it's all a matter of personal taste preference. Some love American aromatics with their added flavors and PG and all, others prefer the Gawith 'strong dark' Brit badboys...and everything in between. Smoke what you like and don't worry about it, it's all good.
By the way...the same thing is true of cigars...from White Owls to Pepins. :twisted: