"Do you think Apple can make any big improvements "
It's not a matter of "can" it's a matter of "If" they will.
Apple has the best engineering group, the best designers, and all the money in the world.... there's simply no excuse not to build a really fantastic phone the next time around.
There's a lot that this phone needs.
If Apple gets serious, the upcoming new model will really be at the top of the Smartphone Sector on it's merits and performance, not just because it sells in massive quantities.
Apple needs to bring up it's image by getting serious, applying themselves, and showing us what they are capable of.
That Apple has allowed Android to become this good, and be a serious competitor, is testimony to Apples burning desire to milk us for all the cash they can.