at the expense of full node operators.
Satoshi talks of nodes running in server farms and a lightweight client being the wallet for the average user. I don't see why the progress of bitcoin should be held hostage by the whiners who are too cheap to run a node on decent hardware, when it was never envisaged that anything less would be necessary in future.
If the "average user" isn't going to run a full node then he might as well not be using bitcoin. If he is willing to pass the security on to someone else, he might as well use an "off chain" method.