If you're really all that baffled about why we're seeing a lot more drop pods now than in the past:
They have existed and been an option for some time, its just now they are a much cheaper plastic kit rather then a forgeworld item.
That's the real deal. As any Eldar player can attest (we went for
how long without a wave serpent kit in 3rd?) it doesn't matter how good a unit is, if there's no model for it you just aren't going to see a lot of them.
As people have already pointed out, they haven't really gotten all that much better or anything. It's just that now there is a model for them, so we see a lot more people taking them.
It's not that complicated, and has very little to do with new rules and applications.
Space marines actually stand up to their fluff now though. Drop pods do seem very risy and dangerous to use (Deep strike near the wrong unit) and if you have a sensible opponent they can cut off isolated drop pods and kill them if they do this enough it can end up crippiling your army.
I'm sorry, I had to laugh at this. "Risk" and "drop pod" do not belong together in the same sentence. Even if you scatter the full distance, the size of the drop pod still allows the squad inside to be well within a foot of whatever they're aiming for, especially since they can drop right on top of their target with no worries.
I don't particularly hate drop pods or anything, but
surely you're joking if you want to suggest that they are risky. The only risk you run is that they won't show up
exactly when you want them to, and even then, they're guaranteed to show up at some point. (Especially considering that most of them will mostly be coming in on turn one.)