I had never heard any of that prior to that lecture, but the more I thought about it, the more it made sense. I certainly remember being an E3/E4 and not wanting any officers to come poking around my AO!
There is still a mentor program of sorts going on, though I don't know how formal it is. Usually, as a PL, I believe you're teamed up with the Company XO (like you said, a senior O-2). I just hope I can quickly ascertain whether he's a dirtbag or not.
The greatest pitfall of a heavy unit is VEHICLE MAINTENANCE.
If you're ultimately headed for a Stryker unit, then bone up on the vehicle's vital stats. And not just it's armament, max speed, etc. Concentrate on it's fuel efficiency; ammunition capacity; lifetime of the power pack; maintenance rotation schedule - these are the things which will save you, and your kids, down the trail.
And, DON'T fall for this trap: hot-shot LT's thinking that they should be in the motor park turning wrenches, as if that's the sole mark of a good PL. Tanker LT's tried to do that to me (I was MI, and the Bn S-2). Turning wrenches is YOUR KIDS' JOB, not yours. Like you said, you didn't like officers hanging around your AO?
The new weight on your collar is best used, to get the NCO Support Chain what they need to get the tasks done. You can break certain things loose than even the NCO's can't. When that E-6/7 finds out that you're smart enough to stay where you're needed, he'll brings you things that you won't normally see.
This is gonna be like a marriage; you're figuring out what your spouse likes/hates, and who leaves the toothpaste on the sink, etc. Fact-finding. You're not going to hit the gournd running; but you won't trip and fall, either.