I don't think adding ring cryptography or stealth addresses would be necessarily difficult to include into BitShares. I'm more than happy to lend my expertise on the matter. Then again, what do I know ?

The other issues you raise need to be addressed as well.

1. You are right that there is some type of amount information that can be used for analysis, particularly the number of tokens moved from 1 address to another. From what I understand Monero Research Labs is considering this problem.

2. VPN + TOR. Most coins are using TOR anyway nowadays ... those that aren't, you can't really do much about it, unless you use a snapshot of the blockchain at a particular time and then re-launch with TOR added.

3. Indeed a problem. Run your own masternode. I will be once I have enough DASH saved.

4. I'll have to think on this one a bit more.