Electrum 2.x (and many other wallets I hope) will be interoperable and support BIP39 in the not-very-distant future.
This is not true. Electrum 2.0 uses BIP39 wordlists, but seed generation is non-standard, so it is not technically BIP39 compliant.
You will not be able to import BIP39 mnemonics into Electrum.