A unified language would make communication easier in theory, but of course you'll probably get "Why don't we switch to one government and one form of currency while we're at it?"
Government and currency are irrelevant since even if you limit it to English you are already talking about different countries with their our governments and currency. My point is that campaigning for a world language is exactly the same as what you seem to be doing, only on a greater scale. By examining it and seeing the problems that stand in the way of that, it should help to point out the problems you'd face trying to unify English.
Again, the important thing is making sure your target audience understands. If you are talking to computer geeks, you'd likely use a lot of terms that non-computer geeks would scratch their heads over. And it's the same with any other profession or sub-group. Even us furs have a few words that non-furs would generally be perplexed by. But that doesn't make it "wrong". It's only truly "wrong" if it fails at it's purpose: communicating with your target audience.
Having said that, I would suspect that with global communication becoming easier and more widely used, we'll likely start to see some merging of language going on, especially with languages that are already very similar. US English and British English being a prime example.
[edited to fix typo]