multisign and stealh addr, are IMHO two of the most important security features since BIP38 and HD wallets.
Stealth Addresses would be difficult at this stage to implement, as the implementation of DW is not finalized and has yet to be accepted as a standard format.
Until Stealth Addresses as they exist in Dark Wallet, are accepted as a BIP, I wouldn't think taking the time to include them would be worth it.
(someone correct me if I'm wrong)
However, I think one problem of the current implementation of stealth addresses in DW is the way they handle multisig P2SH. The stealth address would have to include the spend_pubkey of each of N addresses in it, so as you extrapolate it to 5 of 9, 17 of 33 etc etc... the stealth address will be unwieldy large.
I think if they would just keep the format as strictly P2KH...
Not to mention that implementing Stealth Addresses as they exist in DW would require storing a separate table on the Electrum servers to look up for the OP_RETURNS in order to create the addresses. (otherwise they would not be able to be restored by seed)
tl;dr: It's not finalized on their end, and until a BIP is approved for the "Dual-key Stealth Address which includes P2SH ability" it should not be included anywhere else but Dark Wallet.
Edit: Links for further study. (#1 and #2 are revolutionary and make stealth usable to normal people. #3 is a little ambitious but I would like to see it happen)
1. Database format for OP_RETURN storage and easy lookup.
https://wiki.unsystem.net/index.php/DarkWallet/Stealth#Database_file_format2. Dual-key Stealth, and how it works.
https://wiki.unsystem.net/index.php/DarkWallet/Stealth#Dual-key_stealth3. How the Stealth Address can be used to create shared secret multisigs.
https://wiki.unsystem.net/index.php/DarkWallet/Stealth#Multisig_stealth
