They are good players no question, but I wouldn't put either in the top 15 in the NBA.
Curry, LeBron, Durant, Leonard, Westbrook, Harden, Paul, George, Davis, Towns.
That's more or less my top 10.
After that group, I think Draymond gets into the conversation. You can talk about Lowry, Wall, Irving, Butler, Drummond, Lillard, Deandre, Griffin. Thompson comes into the conversation somewhere around there as well, along with Paul Millsap and LaMarcus.
So yeah, I see your point. I think it's debatable if they are "top 15" as opposed to, say, "top 20" or "top 25."
I think you could argue their value is in excess of some of those names because of their health, consistency, and defensive ability. Whereas Irving, Lillard, Griffin, LaMarcus, and Drummond are all limited on one end or the other, have significant injury issues, or both.
Anyway, the bottom line is, regardless of where you want to rank them, Draymond and Thompson are really, really good, and would be capable of serving as the focal point for a very good team. Despite that, they are clearly the 3rd and 4th best players on the Warriors.
I don't think there has ever been a team with such talented, in-their-prime players as the clear-cut 3rd and 4th best guys on the roster.