The problem with installing another launcher in favour of Touchwiz is that Touchwiz isn't just a launcher - it's a framework, so you'll still have a ton of stuff running in the background. You're actually making the problem worse. The best way to move from Touchwiz to a non-Touchwiz experience is to install a custom ROM on it. I'd recommend something as close to AOSP (pure Android) as possible so that you can then build it up into what you want it to be, rather than being boxed in by OEMs.
I had an S2 and really, really liked it, but Touchwiz was horrible. It looked like it was made for 5 year olds and yes, the battery use was ridiculous. As soon as I put something custom on it and installed Nova (my launcher of choice) it was like a new phone and I never looked back.
I've got a HTC One (M7) now. I've had it for just over a year and it's by far the best out-of-the-box experience I've had with a phone. I have had a ton of different ROMs on it, just to try them, and there are some great ones out there, but I recently had to send it back to HTC because of the very common purple camera tint issue, so I had to get everything back to stock before sending it or they may well have charged me for the repair. When I got it back they'd updated everything on there and it's just lovely.
Other than this phone I don't think I've ever managed to live with what's on it out-of-the-box. But thankfully there are great places like xda where you can turn your phone into something much better.