[ecesena]

This looks more like a bug, where the attacker exploited a function which is particularly slow and forced the nodes to run this function many times.

If the nodes had different implementations, chances would be that only some nodes would be slown down, but the reality -i assume- is that there's only 1 implementation.

Think to mail servers, if they were all running the same os/sw then attacks to the whole system could be easier.

[RexetBlell]

There are actually 10+ independent implementations of Ethereum (including one in Haskell): https://www.reddit.com/r/ethereum/comments/3pdskt/how_many_e...

This was part of the development philosophy, to implement the client (based on the yellow paper http://gavwood.com/paper.pdf that specifies the protocol) in multiple languages in order to find bugs: if 2 clients don't agree on something, then we found a bug.

[komaromy]

There are two widely-used implementations, and more that don't have as much adoption: https://github.com/ethereum/go-ethereum https://github.com/ethcore/parity