The position that most often is a draft loser is QB. Why? Because all they measure is athleticism and and arm strength. But 90% of QB play is played between the ears. It is a mental position, mostly immeasurable in athletic terms.
The most important need is leadership and POISE. Boyer had no receivers this year and his percentage of completions fell as dropped passes were everywhere. But he has POISE and still kept the team together, and didn't complain. One scout counted a game with 6 dropped passes in 15 attempts, so his accuracy stats are misleading.
His arm is not a cannon like Stafford's arm, but it looks at least as strong as Montana's, Brady's or Cassel's. So it is good enough. He also has another important ability. He cannot run, but he certainly does shuffle around the pocket as well as Montana and Brady, avoiding the sack and buying time. But Montana and Brady were not runners either. Most of all he has POISE.
I think the Pats have found another very good third string QB candidate, downgraded for poor results by his Team's deficiencies. Gutierrez should have a lot of competition for third string QB.