Ally McCoist's side missed a series of first-half chances and were abject after the break as goals from Danny Wilson and Osman Sow, either side of Nicky Law's stoppage-time leveller, clinched the win for the Jambos.
And Miller insists he and strike partner Kris Boyd can only do so much if opportunities are not being carved out by their Light Blues team-mates.
He said: "I think we need to create more. We're at home at Ibrox and we need to be creating more chances.
"Kris Boyd is playing - the all-time top SPL goalscorer - and I don't think he's had a chance to score a goal today which is not good enough.
"He's going to be the guy who will probably get the majority of our goals, but if he is coming in from a home game and not getting any real chances to score, then that is something we have got to look at.
"It's up to us to work at it with the players we have got at midfield and find some way to create chances.
"But it was similar on Tuesday. Boydy will get the majority of our goals this season, but if we are not going to get that ball into the box for him, then that's something that needs to be rectified to make sure that doesn't keep happening because he's been brought back for a reason and that's to put the ball in the back of the net."
Hearts' winner came just seconds after Law had pulled Rangers level at the death as Robbie Neilson's side swarmed forward from kick-off and Sow netted.
The defending from both goals left a lot to be desired and Miller admits the late sucker-punch was hard to stomach.
He said: "It's a really, really poor start result-wise. I didn't think there was too much in the game.
"The manner in which we lost our goals was really disappointing. Nobody wants to lose goals from set-plays.
"But to get back into the game at the stage we did - and I felt we deserved it because I still don't think we deserved to get beat.
"But to lose that goal at that time is really criminal."