Iphone 3G really slow, maps slow

I've had my iphone for over 2 years and it used to be faster, the biggest thing I noticed is the maps app is really slow, it takes longer to search for things, the map loads slower, there is a delay with typing. I've noticed slowness in other places too but mainly the maps.

It seems to have started with the last few IOS updates. I turned off blue tooth, I rebuild the phone IOS and restored all my data. It seems like it did help a little bit after the rebuild but it's still slow and not as fast as it used to be.

I'll probably buy the next IPhone that comes out but my wife will use the 3G so I would like to fix the slowness if possible.

Is there anything that can be done to fix it?

Did Apple nerf the older phones with the last IOS update on purpose to force you to buy a newer phone? If so I'll probably move to Android or Windows phones.