Well for a few reasons.
First they took a good thing and kind of gutted it. They really slowed down the PvP gameplay and because of that PvE is also a lot slower since you have very slow supers and two primary weapons with barely anything else. The game feels like Reach when you play it in terms of the slow down, movement changes, and even gun handling. Hard to explain unless you have played Destiny 1 and then 2 and also Reach from previous Halos. Even found a gun that looks and has the same look when fired as the dmr did. The PvP matches are essentially Halo now as well..It is 4v4 and with all your supers and abilities coming back so slow all you have is guns. However in terms of power weapons only one person per team can get it when the ammo comes up every 2 minutes or so just like in Halo. Some will indeed like this but this is not Destiny.
That is in the game, outside I have seen a lot of people fussing about what they have done to the game and all the old things people argued about Reach have returned, deja vu for sure. I've seen multiple adapt arguments, and this is just a beta. A lot of arguing going on and it reminds me a lot of what Reach was like during that beta.