Hi,
That's a good idea indeed. There are indeed some known Unity api or PlayMaker pai that should be used with care and in very specific contexts, but for this to be spreaded to all Actions, we would need some hard data from Unity guys themselves, which we haven't to this day.
Typically, avoid finding gameobjects by their names. Avoid creating and destroying objects and components.
also, a good rule is to design first exactly what you need, until it works as expected, then you optimize, making use of the Unity profiler, pin point what could be a performance hit, and adress that only. If you take n baord optimization first, you'll corner yourself and waiste time for something that will anyway needs an optimization pass when done, no matter what
Bye,
Jean