Are you supplying the answers?
Yes.
The reason Shadowcoin is a non-starter is because it doesn't make a distinction between monetary and utility value.
Over the last year, technology hasn't made a dent in Bitcoin's marketcap. It has continued to consolidate despite the advances that have been made by altcoins in all sorts of utility aspects - confirmation speed, functional diversity, contracts, asset based blockchains etc.
Of the 6 monetary properties, however - Portability, Divisibility, Durability, Scarecity, Fungiblibility and Un-consumability - Bitcoin is missing only 1: Fungibility.
Darkcoin does address this deficiency directly and it does so without mitigating its ability to inherit the rest of Bitcoin's monetary role by way of fully implementing the Bitcoin core code and protocol. That's why the 2-tier architecture is the right approach because otherwise you've got to re-invent the wheel twice and markets don't take too kindly to that as you've already discovered to your financial detriment.