The first part is the one I agree with. Why doesn't /ac queue an action the same way as when you press the key? Normally you can press something and it will queue as your next action. Put it in a macro and suddenly that's not true, making it fail if you clip the animation in even the slightest.

For the second, no. There is a somewhat close feature I do want, however. I would like macros to be able to break (stop) if an action in the macro physically cannot/does not execute (on cooldown, not procced for, player stunned/out of range, etc.) It goes with the above, relying on an order of events, but no finer conditions than that. If the order is broken, the macro halts.