Yes, it’s pretty normal for cow/cutting horses. Obviously the lines vary, but they tend to have more of a fast-twitch response because you need it to work the cattle properly. But their QH so they have to be smart and willing, too - we can’t be doing work if our horse is being a total nut-nut. It’s my favorite kind, because if you get a decent individual, you have the perfect combination of athletic + good minded + responsive.
Other lines produce other types of horses – the western pleasure lines are VERY different from the cutters – and even lines within a type are different. The Peppy San Badger horses are different from the Colonel Freckles, for example.
So I love, for example, a Peppy San Badger (tough and durable) crossed on a Freckles Playboy line (amateur-friendly) – but both sides highly athletic.
King Ranch horses breed pretty true, and their lines tend to be a little spicier than others, because those horses had to go 20+ miles in a day in South Texas humid heat and bugs, so they had to have the “bottom” in them. Hired Hand was a famous sire of theirs. Your mare also has a dose of Miss Gun Smoke too – that line is a little spicier too.