Speaking as someone who's been an Iron Man fan for over 16 years, who stuck with the comic through some of its worst periods (Matt Fraction's runs made me finally give up) - I loved Trevor. Yes, I appreciate the Mandarin is regarded as Tony's arch-nemesis for whatever reason but he's ultimately a two-dimensional pulp-throwback 'yellow peril' villain who even the most talented writers like Kurt Busiek have struggled to do anything meaningful with since Vietnam stopped being a thing.
I actually took far more issue with Killian's last gasp of 'I am the Mandarin!' and his dubious tattoos.
Truth is, Iron Man has some much better villains who'd be easier to frame in a modern context that could be mined from various periods of the comic's history - Sunset Bain, Madame Masque, Crimson Dynamo, Titanium Man, Radioactive Man and Ultimo to name a few. To be honest I'm disappointed they're going with Civil War for the next Captain America and Iron Man films, I'd much rather have seen them tackle Armour Wars. Michelinie/Layton Iron Man still stands as my favourite run for the character.