1. Meltdown / Spectre make the Ledger Wallet very important
2. EtherDelta Exchange would be interesting, so would Bancor, Ox or Loopring

These are my thoughts in order on the matter.

Liquidity has always been the Bitshares hurdle to overcome.

1. The BTS markets work by two parties entering a smart contract on a trade
2. There has to be two parties for the asset mechanisms to work.
3. Not being able to move from outside blockchains onto Bitshares results in vendor lock-in.
4. While many want distributed exchanges they also want the ability to walk with asset in hand and trade for any digital asset with anyone
5. What BTS could do is focus cross chain transactions like ARK or specifically with lighting network nodes

Lighting network might be the best way to play well with other blockchains. I am not certain how the ARK cross chain txns happen but that too is something to explore further.