Even if those were sorted, you probably want to hold out for homomorphic encryption. The threat model of Amazon having all your data is much different from the threat model of anyone willing to bid cheaply enough on a lambda execution having it. OTOH in the latter case, we can probably expect three letter agencies all over the world to be generously subsidizing our compute (for example, by reselling GovCloud at a loss).
BTW modern CPUs support the creation of RAM-encrypted VMs with remote attestation, so you can lower the trust needed in the targets by a lot. That said there are lots of companies that are known quantities, have verifiable brands and may even be considered more trustworthy than the big clouds in some cases because they're local firms.