I'm torn. I like the cinematic aspects, but I'm not so sure that Second Wind is the best way to get it. Also, I think the modular knobs needed to make it more flexible across a wider range of styles are lacking.
Ideally, I'd like to see Second Wind tied to a resource, but on a sliding scale where you can make it matter more or less. Making it an Encounter ability may work out roughly equal, but it doesn't have nearly so much room to tweak.
For example, let's say that SW is tied to the Hit Die mechanic. Well, right there if you aren't using the Hit Die, you probably aren't using and don't want SW. So that's good. Furthermore, if SW gets hit points back based on the Hit Die, it scales by character, but isn't nearly so powerful by default. That gives it room to go up. Then we might, by default, say that HD and SW give equal, but that SW is limited to 1/Encounter. OK, now it's still better than waiting until after combat, but it cuts into your daily resource. You can't do it indefinitely (a nicely appropriate simulation nod).
From there, however, we can adjust with modules. For example, the "tactical" module gives a bonus when Hit Die are used with a healing kit (perhaps requiring one charge per die to compensate). You get to roll an extra die when you use a kit, but you have to declare when you roll. When you use SW, it requires no charge, but you only get to roll one die. That means that burning all that adrenaline in a hurry has strategic cost.
Or using a healing kit out of combat makes HD permanent healing, but using HD in combat with SW makes them temp hit points (nod to Jester) that only lasts until the end of the encounter and cannot exceed your normal total. Use as many as you want, one die per action. That's a slightly different tactical and strategic calculation: if you are about to get heavily pounded and have a breather, temp hit points are as good as any others. If the monsters miss, you just wasted a critical resource.
Combine that with my suggestion in another topic to only grant HD every odd level. That's some real limits on what you can heal, but still very helpful.
All of that has obvious and easy ways to scale to make it more or less cinematic, more or less simulation, more or less gritty, more or less epic. As with all knobs, the key is to make the default useful but somewhat restrained, to give room to turn it up or down.