I agree - think a bit and write something decent, but in the words of Scotty: "The more they overthink the plumbing, the easier it is to stop up the drain".

You are conflating good overall design with sweating the small stuff. If the overall design is good then the problematic bottle neck code can easily be identified by the schlub and fixed in isolation from the rest of the code, especially if there is a good suite of unit tests for the code.

Any army that puts itself in a position of depending on a single nail for success is doomed to failure. Bending an initial design to anticipate future problems most likely wastes time now and probably doesn't help with the unforeseen problems that actually arise in the future. Anticipating a missing nail or any other single detail is hard and time consuming. Ensuring there are sufficient blacksmiths available is easier, prevents the issue and allows a better design of nail to be adopted in the future if required.