Let me put it this way. What if there was a specialization that gave players stronger shields? Then that five shot BR you're using is a five shot on some guys, and a six shot on others. It means getting into a BR fight with someone without realizing it's not a fair fight. It means the understanding you have about the rules of the game and your own capabilities versus your opponents goes out the window, and you never know when you engage someone if that's a good idea or not.
That's not too far off from faster recharging shields. It's one of those foundational rules of the game: I know how high this guy jumps, I know how many shots I need to put on him to drop him, and I know how long I have until his shields return. Only, some guys will recharge faster than others now, and the only way to find out who is who is to get an unhappy surprise.
Now as I said, to a degree this has always been in Halo (surprise! I has rockets). But I'm finding that there's a line I'm uncomfortable with crossing, and things like the faster shield recharge is a ways across it. It's exactly the kind of thing I got nervous about when specializations were announced. Different people draw the line at different points; I think I'm pretty far down the line to being readily accepting of the changing nature of Halo. But there's definitely a line at which I get uncomfortable, and we're up against it in some ways with what Halo 4 is doing (on just a few elements; I like a lot of what 343 is up to).
I'm still not sure yet how to fully articulate exactly where that line is. It has to do with knowing that everyone on the battlefield is playing by the same set of rules. They can get some different toys, but they are bound to the same set of base rules we all follow. But some of the specializations feel like they are shifting into letting players tinker with the base rules they have to follow.
How about a perk to let you jump go higher? Or carry a 3rd weapon? Or dual wield rocket launchers? These are all over that line, but to varying degrees. It's the same feeling I had when I saw Armor Lock in action for the first time, understanding what it meant for gameplay. Giving some players faster recharging shields - or some the ability to pick up grenades - crosses it as well. That base set of rules isn't just changing, we're to the point where players are starting to be able to pick their own. Obviously I'm going to play it - a lot - to see how it goes. But I am really very nervous about how it will play out.