It's exactly the same amount of general leveling. If anything, 10 levels feels less as you hit a new level much quicker (twice as quick).
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Anyway, came here to see if someone has already made a post about this, and sure enough x)
I would be extremely happy if they went back to 10, 5 seems awkward to me. I don't think this 'confirms' it, but it does seem more likely now for sure.
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Yes, god forbid every single piece of content isn't for people who do LFR exclusively.