What would a blockchain designed to support tokens look like?

[BiggestFish]

Since ERC20 tokens appear to be the main reason why Ethereum has taken off this year, I was wondering what optimizations could be made in designing a blockchain that simply facilitates transfer of tokens. No smart contracts, no mutability, etc.

Would it just be Bitcoin + Colored Coins? Or is there something clever that can be done?

[CoinHoarder]

I guess it would look like Counterparty or Omni. The idea has been around for quite a while. Omni (formerly Mastercoin) is older than 99% of most alt coins.

And yeah, Omni/Counterparty are effectively Bitcoin + colored coins + a little bit of smart contract logic to allow issuance and exchange of tokens.