It might be my cynicism, but in the PL literature I find "intuitive" to be a very low calorie word. Obviously you would describe your own system as "intuitive" what are you going to do, write a paper that says "we have a complicated and difficult to understand system S that..."

"intuitive" is very subjective, I think. I know lots of PL people that think that functional programming, for example, is intuitive. After many years of study and practice, I too find functional programming intuitive, but I can remember a time when I did not, but I could still program. From this I conclude that something being "intuitive" is very subjective.

Expressive power, on the other hand, I think we can put an objective definition on. My favorite take of this is Felleisen "On the Expressive Power of Programming Languages." Of course, what use is something being powerful?