I think what you are looking at is app limits at work. Apps must be limited in size to run on the 256 devices. That said I will never have need for the Transport app so why have it clouding my Drive experience.
Originally on symbian Nokia Maps had navigation integrated, but later navigation was separated into the Drive -application. The idea was to make starting navigation easier.
LOL! I didn't even notice that. It shows you how often I use navigation on my N8. I've pull up maps and checked the setting and saw the drive setting, so I didn't give it a 2nd thought. I see it separated now. I am running Symbian^3 Belle.
I am hoping that it will integrate with Nokia Maps + Bing search. Right now, apparently, when you do a Bing search and get local resuls, only Nokia Maps comes up as an app to use, no Drive. When you open Maps, you see a link to get direction, but it just uses the Maps, not Drive. It seems there is no shared info between Maps and Drive like there was on Symbian. Hopefully, it's moving in that direction, because the Symbian version will do live traffic and reroute you.
Isn't transport already integrated on a way to Nokia Maps? Just depends on your country/region if it shows up.
Also one thing to keep in mind is that Nokia Maps costs for other Windows Phones and you can buy it from Marketplace.
Nokia Drive is all exclusive to Nokia with free offline navigation, voice guidance. So there's one reason for it to be separated.
Myself actually quite like that they are 2 different apps as it's easy to start and you have those big buttons right away on Nokia Drive.