Those are the exact 5 I'll be watching, and each of his reasons are succinct and on point. Well done piece of writing by Joe Schad.
Some of these stories will, obviously, take longer to unfold than can really be determined during this phase. Things like the rookies adjusting to the pro game, getting their assignments and chemistry down, or how quickly Tannehill snaps back into form. But some things, like how quickly Raekwon starts taking charge of the front 7, I think we'll be able to tell right away.
The passing game usually takes until around game 4 of the regular season to start firing on all cylinders, so don't be surprised if we look a little hot and a lot cold during pre-season with Ryan coming back after an extended layoff, working in two veterans WR's (Amendola and Wilson) and two rookie TE's (Gesicki and Smythe). Tannehill will need a lot of reps to get there, so let's be patient.
I will not be paying much attention to the trenches yet. The OL/DL play is nearly impossible to gauge at this stage because until the OL gets pads on (and can grab effectively), the OL production and development is minimal. Thus, the DL effectiveness is a mirage and cannot be properly evaluated.
Likewise, at this point of the season the run game is in spandex, so we learn nothing. Sure, scat backs look fast and quick … when DL and CB's can't get an arm on them and LB's and S's can't line them up and thump them into the cheap seats. Power backs look fat and sluggish, and everyone is disappointed with them. LB's only look good when pass rushing against air. Everyone is open. Every QB is generously throwing picks. Some of the stuff just isn't worth fretting about when they do it poorly. I'll be taking a few choice positives here and there and looking to see if it becomes a trend. But other than that … let's look at the timing, organization, route running, athleticism and hands of the WR's, TE's and RB's. Very little else translates. For defenders, we're looking for how well they know their assignments and how well they capitalize on those generous QB's.