The fact that you get them for playing flaws is key -- they should appear when you do something in-character that the power-gamer in you would balk at. "It's more advantageous to have the bump in accuracy provided by an extra attack here, but I'm playing a reckless character, who is going to go all out!"
In general, this takes care of the min/max potential inside itself. A narrow flaw that almost never applies just doesn't generate much Inspiration, because you don't actually play to it very often. A broad flaw that constantly applies might generate more Inspiration -- but you're going to need it because of the extra challenge you take on by willingly doing stuff that's more risky.
Because of that dynamic, Inspiration points reward folks who do dumb stuff that's in-character. They're likely to be used (and needed) more often by more outgoing players. But those players will get into some more noise.
To reel in some of the less enthusiastic role-players, you might consider being DM-proactive. Presumably you know of their bonds, ideals, flaws, etc. Make an adventure or a villain or an encounter that specifically targets that. Even someone who half-heartedly roleplays should manage to stumble into a point or two of Inspiration when the adventure revolves around them.
But it's also unnecessary. The players who don't want to RP their flaws won't get Inspiration and also won't need it as much, so it's fine to not give it out to 'em.