I think DMR, BR and pistol are perfectly fine. Just tone down AR and SMG just a tad bit. They should still be viable weapons but right now they feel cheap to use. DMR is a beast and I think the new scope helps to balance it somewhat by obscuring your vision a bit.
It's a fine, fine line of balancing that 343 is doing.
We as a community are obviously split already. I've read competitive forums saying they want BR starts back...ugh. Yes, that worked in Halo 2 and Halo 3, but Halo 5 is a different beast.
Then we have the other side saying, nerf the AR...but still keep it as a starting weapon with the pistol.
My fear is that I personally do not want Halo 5 to become what Halo 2 and Halo 3 by default were, which was the start with crap and keep getting spawn killed till you get better weapons...and return the favor to the other players who were doing the same to you.
In otherwords, when you spawn in the game, you shouldn't be so weak that you have to pick up weapons on the field in order to be remotely successful. I totally disagree with that kind of Halo, which is what SMG starts were in Halo 2 and AR starts in Halo 3.