I know you said you cleared all the caches but did you wipe the cache partition ? That's always a good idea after any update anyway. If not, try that. Boot the phone in safe mode and turn on battery saver to max. If that works it's probably a bloatware, er, preinstalled app causing excessive processor or memory use. The preinstalled facebook app is a known kiiller of phone performance just as an example. Hope this helps or at least points you in the right direction.
I am curious.
Did you try booting the phone in safe mode and running it that way ?
Hold the power button and when you get the 3 options, power off, restart, emergency mode, press and hold the power off until it turns green and says safe mode. Also change your battery saver to max.
These are not cures by any means but may help find the problem..
I've had the same problems since I got the phone. I don't have that many apps, all my photos, videos, music is stored on an SD card. I've cleared everything I can clear. The phone lags so much I can't even answer a call before the person hangs up. Worst waste of money for a phone. I think the main problem lies in that 12 of the 16 GBs of memory are tied up in the system and preloaded apps that I can't get rid of. Seriously considering scrapping the whole phone and service. Lied to at the store on multiple accounts, horrible phone. Really no reason to stay.