Chief's new suit was supposed to be up urgraded by Cortana, while he was in Cyrosleep. Cortana at the beginning of the game, when Cheif exits the cryo-pod,said that she upgrade his suit. As for humanity's weapons it could be that the realistic difficulty is Legendary, because anything will die with enough bullets.If one has the idea that tier 1 technogy can't be kill by tier 3, they would be wrong because in Halo: Combat Evolved you fight Sentinals kill them. According to Halo wiki Humanity jumped to tier 2 technology towards and at the end of the human covanent war. The UNSC Infinity is a Tier 2 classed ship. Technological tier also so doesn't mean combat effective-ness. Tier 1 is world building technology. So that doesn't mean more combat effiency. In the terminals of Halo 4, Humanity was actually winning for most of the time in the war against the Forerunner. Also Human weapons have been more effective when combating the Flood, as apposed to Plasma and light based weaponry. I don't think there's an explanation for how updated weaponry, like the Battle Rifle,arrived on the Forward Unto Dawn. Although, the Covanent could have been raidering UNSC ships and one could on happen to get free and drift toward the Dawn, but this is only a purly speculative idea not really part of the Halo Canon. Other than that the Infinity most likely brought new weapons,like the SAW or Sticky Detinator, with it. The biggest flop in Halo 4 Canon is really how the hell are marines breathing in Space without some kind of EVA Suit or helmet in the Space Station mission. Where Chief sees the Composer for the first time. There's a breach in the Station intregrity and later in the mission Covies come straight through it. No depressuration and no lost of atomsphere. [Edited on 11.16.2012 3:27 PM PST]