The original smart-contract language, E, is almost nothing like Solidity. To focus on Turing-completeness, it's true that E is Turing-complete and has an `eval()` primitive, which normally would be dangerous. However, E both comes with sufficient tools to prove that any given instance of `eval()` is safe, and also to limit Turing-complete behavior when needed.

Specifically, in E and Monte, we can write auditors, which are objects that can structurally prove facts about other objects. A common auditor in both languages is `DeepFrozen`; writing `as DeepFrozen` on an E or Monte object causes the `DeepFrozen` auditor to examine the AST of that object and prove facts.

There's a Monte community member working on an auditor for primitive recursive arithmetic, inspired IIUC primarily by the EVM's failings.

The DAO hack happened because of a bug class known as "plan interference" in the object-capability world; these bugs happen because two different "plans", or composite actions of code flow, crossed paths. In particular, a plan was allowed to recursively call into itself without resetting its context first. EVM makes this extremely hard to get right. E and Monte have builtin syntax for separating elements of plans with concurrency; if you write `obj.doStuff()` then it happens now, but `obj<-doStuff()` happens later.

So, uh, yeah. Smart contracts aren't a bad idea, but Ethereum's not very good.