alt Hacker NewsI know it's a common pop science factoid, but there's actually no evidence that language difficulty has much to do with becoming a lingua franca.
Russian is commonly viewed as a difficult language, but it become a regional lingua franca in their sphere of influence. The only reason we aren't speaking Russian is because they lost the cold war.
I do agree that Mandarin speakers might become more open to Pinyin if more foreigners started learning the language. I'd also point out that English and Romance speakers find Mandarin difficult. For Mandarin speakers, is their own spoken language actually difficult for them? They might find English to be a difficult language.
English is one of the most difficult languages to learn, because there's so many irregular sentence/word constructions + irregular pronunciations due to vowel shift + foreign loan words like French/Latin that must be pronounced differently.
Mandarin eliminates all of these problems. The tones and characters are difficult, sure, but questions and answers being grammatically identical along with consistent pinyin is a lifesaver.