Yeah, as fucky as English is, as hard as it can be to learn, it's currently the lingua franca ;)

Plus, because it's a language that loves borrowing words and phrases, it's already set up with an ease of integration to a limited extent.

At this point, any effort to displace it as the default is going to cause as much trouble and hassle as it's place as the default does.

That being said, a language like Esperanto would be a better choice overall. It's kinda like how Latin can serve as a neutral and fixed language because it's dead. Esperanto isn't dead, but it's similarly fixed, and not tied to a single culture, so it would work. Then again, so would Latin