User blog comment:Khalael/Canon Policy Discussion 1: Space Marines/@comment-2253300-20131103062045/@comment-3258762-20131103090938

I would just like to point out, and not to undermine what anyone has said, that one of the reasons the Space Wolves do not have successors is the fact that they are, at times, overstrength, having from time to time reached numbers as high as 10.000 marines. Their Great Companies serve as independant chapters, who just so happens to be "guided" by the Great Wolf. So, whilst it has a lot to do with the mutation, I think it is also the fact that the Space Wolves simply don't want to have them anymore, and don't really need a successor chapter.

As for the Salamanders, I think it is plausible to make a Salamanders successor, and as such they should be allowed, but they would probably often be understrength due to mishaps with the Gene-Seed (The already high rate of mutation in the Salamanders, plus the quality-loss from repeated "use" if you get what I mean, would mean that the gene-seed is extremely unstable) and such should be directly outlawed from being overstrength, even if they are a crusading chapter who pick up recruits from every world they visit.