I was personally disappointed that nothing unlocked after I beat the campaign on legendary by myself. I was hoping for the gold visor (called Legendary), as that was the gift, along with mkVI armour, in Halo 4.

There hasn't been enough time for me to play enough multiplayer to see the frequency of opening req packs. However, if I open 100 packs and I still don't get any armour that I'd wear, I'd be a little miffed. I'd really like the option to buy armour/helmets/visors with req points, even if the cost was high. If it cost me 1000 points for a common helmet, I'd pay it. 5000 for uncommon? Fine. 10000 for rare, ok. 15000-20000 for legendary, still worth it if I can get the exact armour I want.