I think it all depends on the user.

If you look at the world of Mobile device users there are two groups of them, you can call it Us and them.

We love the fact that we have new Maemo devices
They love the fact their new nokia

We want to load anything we wan on our device
They want to EASILY find and load cool new farting apps on thier phone

WE are buying a platform to define an experience
They are buying an experience delivered by thier phone

What we cannot forget is that (most likely) 90% of the people who will buy th en900 of future Maemo phones will not be spectacularly tech savy never mind developers. They want something that "just works" is easy to work with and is fun.

With this said I think that nokia should bundle Ovi store or some analogue with Maemo devices, if the you do not want to use it, you understand the power of the technology and the platform and can go get it else where. As we have already seen on Symbian, just because it comes with Ovi, you are not forced to buy through Ovi.

On sharing app's, It should be dependent on the developer, It will be up to determine if they built free-ware or not. If Ovi can act as a licenses mediation tool, more power to it!