I'd love some of the early Dota 2 elements (recycling and gambling wins for bonuses) to come into play too. Obviously making it easier to browse and sell unwanted REQs would be nice too.Reqs mean that we get free, extended support. I'm glad it worked out for them. I just hope they refine it in Halo 6 ala Hearthstone, like being able to craft (spend RP) on individual items and lower the RP price of special packs.
Other than that I think it'd be nice if we could directly spend RP on items, even if it were very expensive to do that, that way you could grind a la Reach for the things you really want without the RNG worry if that floats your boat.