Pop is distinct from other folk forms in that diction is not highly-prized, rather that the message and emotion contained in the lyric is being expressed the way the vocalist wants it to be. This is also why lyrics are misheard and misunderstood.
Add to that you're also listening to several other things going on simulatenously and it's not surprising that certain words and phrases are 'lost' in the translation.
The point about the UK's regional dialects and accents is also interesting: most overseas students of English are taught a standard sort based on BBC or received pronounciation. We're used to those from our own neck of the woods speaking not only quickly but using local variants of English and slang as well. The BBC itself has always welcomed regional accents: the criteria to read the news, say, is that you can be understood clearly with whatever accent you have. Huw Edwards has a broad but clear Welsh accent but it's not a problem to understand him.
Northerners tend to stretch and flatten the vowel sounds too so Barney sings in his accustomed Salford accent. I don't think anyone would call him a gifted and natural vocalist but his voice is unique and it is perfect for the music he did with Marr as well as with New Order.
I was listening to my Bradford 86 boot the other day and noticed that his voice now is different from then in that he doesn't slur as much and it's got deeper too! It could be down to having better monitoring, mics etc as well as having the promptscreens reminding him of those lyrics he can't remember in his old age, despite him writing and performing them hundreds of times!
I think it's "We're like crystal" as in giving the appearance of being solid, beautiful but also fragile but only Sumner himself could know that for sure. I like the ambiguity of his lyrics.