I hunted all last season with a TMR sitting on top of my 6.5WSM. 655yd muley on the ground, the TMR did just fine. I never felt the reticle was too thick or the open center too imprecise. I don't mind it at all.
If Leupy is truly coming out with an MOA-TMR they will have a smash hit on their hands! People have been begging for that for years...
OP- Another great option for your Leupy is Holland's ART, you can get either MOA or Mils, check it out:
Holland's Gunsmithing & Shooters Supply
Just click the link called "Advanced Reticle Technology".