Not really my thing, I've not the first clue about how to do something like that?
In all honesty, the home button has been doing my head in for a fair while, having to press 9 times before anything happens, and using the assist thing as an alternative is just a pain in the arse, so it's just speeded it up for me. Plus I hate the EE network and Orange/T Mobile with a passion since they've all joined forces to create the worst network on the planet and ruin my signal that had been OK for 15 years. So.... time for a change, maybe?
I'm guessing this 7.0.2 update doesn't address any of the problems the iP4 has encountered, and only the 2 things listed in the pic above?
Yeah I don't think it fixed much, I installed it on an iPhone 4 and it's still not nearly as fast as the 4S
About the home button, wow I know how you feel, I suffered from the same thing on my iPhone 4 and it really is annoying..
I'm a bit of a technic person so I just took it on myself to replace the button by myself, it cost me 2$ and about an hour.
It was well worth it, works like a charm now.
But yeah I say go ahead and upgrade your phone~ it seems it's time to do so!