https://www.bitcoin.com/choose-your-wallet/multibit
if you want just a temporary store, there is blockchain.info
if you want a hardware wallet there is trezor, keepkey, ledgerwallet nano, case
I think they are looking for a wallet that is using the same kind of seed than electrum and as such can restore from an electrum seed. I dont think there is such a wallet, unless you know enough to convert the seed
-> https://bitcointalksearch.org/topic/deterministic-wallet-compatibility-matrix-1000544
It is that way for technical reasons (it is hard to unify standard) or developers just care about that function?
You can get the private key for each electrum address by right clicking it and selecting "private key" on the menu. If a new version of electrum uses a different seed restoration method to your old one you can import a list of private keys from your old wallet. Updating would be awkward but not impossible.