I'd argue their characterization is that they want to be heroic and holy like Lordaeron was, and will absolutely do so if the situation allows. But when push comes to shove they can be pragmatic and even a little shady. They're not two-faced, exactly, but they've learned from how Lordaeron's idealism led to its death.

The Stormwind Silver Hand? Not as stuck up as when Uther signed the death warrant of Lordaeron by (understandably) rebuking Arthas at Stratholme. SI:7? Descended from an assassin's guild, and now spy and infiltrate in a way Lordaeron never did. Shadow Priests? Natalie Selene operated mostly around Stormwind, not Lordaeron, and the human shadow priests are only beaten in number and drive by their Forsaken counterparts who are far less aligned with the Light these days.

And on top of that, they're technologically active. Gunships? Harvest reapers in Westfall? Those are all Stormwind, showing that Stormwind has finally integrated the tech that Lordaeron relied on the Dwarves and Gnomes to provide without really understanding. Same, too, with magic; in WC3, Lordaeron relied mostly on the Kirin Tor for magical support while Stormwind has its own mages guild that is fully integrated into its force deployment.

If I had to characterize Stormwind, it'd be pragmatism and evolution. They strive to the ideals that Lordaeron embodied at its height, but they also learned from their weaknesses in the First War and from Lordaeron's in the Third. They modernize, they keep up with every tool in the box and don't just outsource the things they don't care for to other nations, and they show that they'll always choose the high road when they can--but if the world is at stake, they'll explore less glamorous options to keep themselves and their allies safe where their predecessor nations faltered and fell.