...but there were only 2 precision primaries 3 and Reach, instead of the 4 we have now. I'd say that the current sandbox as a whole is balanced better than either. In 3 the primaries were pretty evenly matched against each other, but dominated the AR. In Reach, the DMR was just flat-out the best like 90% of the time, with the NR and AR being somewhat closer together.
I feel like the current state of the H4 sandbox is right about where it should be. Each primary has a pretty clear niche, with the updated BR/Carbine being the short/mid range champions and the DMR/LR winning out at long range. I still hear people complaining that the DMR is overpowered sometimes, but I feel that those complaints are more so due to personal preference than a real game imbalance (at least since the update). The automatics fit in nicely now as well, and provide solid close-range firepower. The AR is even good out to nearly mid-range if you're accurate and have some trigger discipline.