Personally, I only tr my characters to a third life (to get the stat increase) and that's it. As you point out, you don't have to "farm" quests like shadow crypt in a heroic tr. And I don't. I run most quests once or twice. And it's ok to do once, or twice, but all the way to completionist? No thanks, not for me. It's still a "grind" since I prefer to play at cap.
Don't get me wrong. The current heroic tr system is somewhat fair (almost). I'm not forced to tr any more than I choose. It's fair provided the past-life bonuses are marginal and don't make it seem "mandatory" to go for completionist. (Something like the +2 spell pen for wiz half-lives is an example of something outside of that since 3 wiz past-lives versus no past-lives seems like too much of a difference.) I can give you the plus 2 stat completionist bonuses and other small bonuses in things like hp. You are full value for those benefits, but I can still go into an Epic Elite quest on my 2-time tr and contribute. So I don't have to "grind" any more than I decide to.
But where I have a problem is with Turbine's new proposal for epic tr. Why force everyone to go back to level 0? Maybe I want an epic past-life bonus and I'm ok with redoing level 20-28, but can't stand the thought of heroic levels. Why force me to redo that "grind". (I'm not making it a "grind" by farming certain quests, to me it's a grind no matter what.) Why reset destiny xp to 0? I might be ok with redoing levels 20-28 in a fun ED, but not OK with spending time in a bunch of "unfun" EDs. That feels "grindy" to me.