Foreign names should be spelled in English so they sound as close to the original language as possible in my opinion.
But even that doesn't work! See my previous post, where English speakers (at least in the US) pronounce the 'j' on Beijing as a French 'zh' sound for no good reason. It's just... silly. And wrong, dammit!
I mean, it's totally OK if you read Tokimune as Tokeemoon. That's how it would be pronounced in English, anyway. But Beizhing? Really?! Just read it like an English word!