There is absolutely a performance hit for larger numbers, because they take up more space in storage and may well be in different formats.
As to what performance hit is questionable though, but there are benefits beyond those.
Ease of interpretation, as much as some players might deny that would benefit a lot.
So we'll be getting Wrath endgame numbers then? If thats true I think they should have gone further and took them to Vanilla levels or we will be facing the same problems again in the next expansion or the one that comes after.
If they did redo all the combat code in the game, it would take so much out of development of new content that we would actually lose something.
Hell, the whole reason we got to these numbers was because of positive reaction to the implementation of a new feature that warranted better gear, and thus screwing over with their existing planning back in wrath. They gave us something we wanted and now are fixing the negative side effects. I really don't see the problem with that.
32 bit machines can handle 64 bit numbers for arithmetic purposes. It just takes a few CPU operations instead of one. Problems start with memory allocation, and the unbeatable limit for 32 bit machines
I have enough of EA ruining great franchises and studios, forcing DRM and Origin on their games, releasing incomplete games only to sell day-1 DLCs or spill dozens of DLCs, and then saying it, and microtransactions, is what players want, stopping players from giving EA games poor reviews, as well as deflecting complaints with cheap PR tricks.
I'm not going to buy any game by EA as long as they continue those practices.
I have a feeling the OP is having a go at us here folks. It's called baiting.
That said, I'm all for it, but if they didn't do it I wouldn't care. At all. I'm not sure why people are so against it. The reasons for being against it are all in their minds.