By doing this it submits to the frame that we should be regulating how users want to specify spending conditions
While I understand the impulse to want to give developers as much freedom as possible to make more expressive scripts, I don’t think “make bitcoin maximally expressive” is the correct frame, either.
Ethereum has maximally expressive contracts, and what has it gotten them?
Clearly there are certain behaviors we want to avoid if we don’t want bitcoin to end up like Ethereum. I’m sure you would agree that we should never make bitcoin script Turing complete, for instance.
One of the most important tasks ahead of us is to define where this line is and what constitutes stepping over it, so we can be confident that the new behavior we enable is net positive for bitcoin.
Then, I think the optimal strategy would be to get as close to this line as possible, without stepping over.