[apeace]

Can't speak for thefalcon, but implementing Segwit (or any change) as a soft fork creates the possibility of an eventual chain re-org, as well as the possibility for non-upgraded miners to accidentally work on an invalid block. Soft forks have all the difficulties of hard forks (requiring 51% of hashing power to work), with those two additional disadvantages.

See this comment: https://news.ycombinator.com/item?id=14866911