Improving HTC Sensation XE somehow I have an HTC Sensation XE and the smartphone is becoming slower and worse every day, expecially compared to my Nexus 7 and Samsung Tab 2.

Android on the phone is slow and lagged ( I have to wait even 6-7 second after clicking somewhere), the battery depletes very fast and the phone itself becomes very hot if I do something "intensive" like using google maps.
the Android version on the phone is 4.0.3 and as far as I know, there is no update.

What can I do to improve the phone? It's market value makes it not worth to sell and it is still working, so I would like to find a way to fix it somehow, what can i do?
I like a lot the vanilla Android of the Nexus 7, there is any way that I can put a plain android on the HTC, keeping all the functionalities? I dont care of Htc Sense, but I want to be able to use the camera, 3g, wifi, GPS and so on.

Maybe some kind of reset would be enough to bring it bask to it's best days?
Do a system wipe and reinstall. This significantly sped up my Sensation.