Well, you have to start shooting things up quickly in the beginning if only to set the tone and gameplay expectations.
I think we all agree that past that point, a longer portion of exploration would have been great. If you just gave us some of those valleys to explore without much in the way of Covenant attack or better yet have us drive down to that awesome Requiem floaty installation thing when we first get the Hog then drive up again.
I'm sure we're on the minority portion of "I'm just driving around and people area talking, this is boring" to "awesome ambience" curve.
Speaking of which, while my feelings sort of shift around over time, I ultimately think the things they definitely got right in the first portion of the game were the Infinity teases (though yes, optimally I wish we had essentially another mission's worth of time before it all came to a head), and especially the leadup right to the Didact's release. It's an awesome moment to me because as diehard fans we knew what the "ancient evil" was going to be (whether or not we should have is another question) but unless you're looking really hard for it on Forerunner, you don't actually know what's about to go down until you make that final teleport and the Cryptum is right smack in your face and the music cue kicks in.
My first thought: "Cortana, we've made a big mistake."
