What about ALR's ability to keep the lineup from being too lefty heavy?
You meant Righty heavy I presume. Anyway, to me, it's a critical factor. I think you can argue their relative merits either way, but without LaRoche, as I saw it there was only one "effective" lefty in the lineup. (I don't count Span because as leadoff he isn't protecting anyone.) I think it is important to have a #2 lefty and a lefty batting after Zimmerman. Without LaRoche, you'd almost have to bat Harper #4. Now you can keep him at #2 and bat LaRoche #4.
My biggest problem with all this is where are you going to bat Werth? Almost has to be #5, and he really hasn't proved effective batting in the bottom half of the order. I really do wish we hadn't acquired Span, and that we were going with the 2012 lineup.