Meaning is socially constructed. Language has never been in a static state, but rather it has evolved over time. Sure, we need shared rules to help language translate across a broad range of interpreters, but the general shift is that meaning will change as different people make use of the technology of language to communicate. Shakespeare added something like 500-1000 words to the English language. He just made them up. People bought into his usage and eventually started assigning a shared meaning to them to help communicate between themselves, but his words have also changed meaning over time, and that shift hasn't diminished people's ability to communicate to each other. These changes sometimes increase, and sometimes decrease the range of interpretations.

I say all this to posit that "they" could work out just fine as a gender neutral pronoun if people buy into it. Honestly, I don't think it adds confusion in this case because every sentence is written in context and we naturally interpret whether someone is referring to a singular person or a plurality of persons from the context (usually embedded in the sentence itself). You almost have to intentionally misunderstand a person to be confused by it. That being said, I still use "he or she" when I speak, but I see no reason to correct someone when that person uses "they" as a substitute. He or she wanted to convey information to me and I can successfully interpret it. Communication happened!

TLDR

I don't use "they" as a gender neutral pronoun, but there really isn't a good reason not to.