We need functional and fully trustable non-full clients or else we die.
We do. its called Electrum.
Huh, did you were here a couple days ago? All SPV wallets suffered from a high risk of non valid transactions due the blockchain split, and guess what, Electrum is a SPV wallet. Basically any wallet that wasn't an updated core wallet was under risk.
You: We need non-full clients.
Me: There are some.
You: But they aren't full clients.