Atomic Swaps are not implemented ASAP for both the BTS token and all of its its SmartCoins.
The Lightning Network and Atomic Cross Chain swaps will enable high interoperability between blockchains. The DEX is no longer Bitshares' killer feature. There are better designed (with no derivatives or IOUs) DEXs coming.
IMO, bitUSD is Bitshares' last hoorah. It is the oldest, and most trusted, decentralized $1 USD-pegged derivative in existence.
Making Atomic Cross Chain swaps work for bitUSD could establish it as the go-to option (a base trading pair) for other better designed DEXs. They will need a trustable USD pegged token.
If Tether gets Atomic Cross Chain swaps first, then it might be game over for Bitshares... they already have the centralized exchange market on lockdown. The decentralized market is the only market left for bitUSD.
Forget the crypto derivatives like bitBTC etc, cross chain swaps will make them obsolete. FIAT, stock, index fund, and other commodity derivates are a different story though. Bitshares' killer feature is these types of SmartCoins, not the DEX (unless cross chain swaps are implemented in the Bitshares DEX that is...)