Ok, as I've become more experienced, I've noticed something odd about the way players of certain level groups play. Here is what I have gathered.
So to sum that up, the order is ( for vehicles) Hawk, Razorback/Grasshopper, Tank, Hawk
I would make one change to your observations (pretty good ones by the way) velvet: You reach level 50 and still not have a full grasp of all the aspects or how to play the game. I myself am just starting to get the hang of zones by playing in the forum room. The forum games can seem overwhelming to the unprepared but you get a chance to see what can be accomplished in terms of skill and gameplay in just a few hours.
I would point out that KDR is not always a direct indication of skill. There are a lot of d-bags playing that have huge KDRs but play to maintain their stats not the objective of the game.
Experience means you will recognize a game where the other team has a plan and is slowly starting to overwhelm and accomplish the objective (if they do it without spamming your base with outposts pay close attention and learn). The best part is when you come to recognize how a few small things you do will help turn the tide. Before the advent of the grizzly one or two people with grinders and prox mines could set the other team back on their heals. Now you have to be much more creative.
Balanced or nearly balanced games which provide a lot of back and forth games are the reason (in my opinion) most of us enjoy SH.
I waited until November to start to learn how to fly (a big mistake on my part). I will never be a beast in the air but with some help from some very patient forum members it isn't a quick loop of spawn,fly/die anymore.
You mention the op spam, but once you get the grinder skill it is irrelevant. I'll be hosting a noob room over the weekend so that skills can unlock easier.
A noob room would only help if there were actually a way to limit the level of players that can join it.
Of course, what constitutes a noob can also be considered a debatable point. I'm roughly 400XP short of level 30, but still feel like a noob when I hit a busy server. I definitely feel like my skills are finally coming around, though. I was playing Maw of Despair solo last night on medium difficulty and managed to make it to the final round before being overwhelmed by the 20+ Apex Warriors that show up for the finale.
I agree the grinder skill is a relevent skill for base protection and I have yet to unlock it. I tend not to spend much time at the home base unless I am trying to push back a BR. When I play defence I use weapon mods. A quick double shot with the MAW is handy when protecting a zone, flag or when you have those pesky hawks dropping in with stealth trying to stomp the kids
This is more of an open question to the forum. Is it possible to unlock the grinder skill in the Prospector maps?
(I took out 8-9 fully loaded razorbacks the other night on the Ballard Crossing map.....nada....nothing...what the fudge?)
Phoenix makes a very good point about getting better. It will take hours to hone small tactics into a cat like reflex.
Complicated things like homer missle dodging while dog fighting take much longer.