I think you mean "not very open", as in not community built, or some other type of
extreme openness like that (open <-> close is a scale, it's not black or white). But I'd argue that while Android should remain open source (you can use the source once it's ready), it should be even more "closed", in the sense that Google needs to have a lot more control over what the manufacturers/their partners can do with Android.
Why? Because it's the only way to ensure a cohesive "ecosystem" that helps not only Google and their Android users, but also the manufacturers themselves in the long run. After all, if everyone had their own little fork of Android, and there wouldn't be an "ecosystem" anymore, that wouldn't benefit them at all, as these days it's all about "platform wars", and splitting one big platform into 10 different ones would actually hurt the manufacturers, not help them.
This is why I think Google needs to "close" Android even more i.e. standardize it a lot more, and even demand from manufacturers to release their drivers. It would be awesome if they told them to release open source drivers, but even closed source ones would be useful, because if everyone did this, Android could actually (eventually) work like Windows.
You would be able to install "Android" on any 2-3 year old smartphone or tablet. But that's only if the manufacturers would be forced to release those drivers and maintain the support for that amount of time. And that's only possible if the Android ecosystem becomes a little tigher/more closed, or "less open" (as in manufacturers can't do whatever they want, and they must obey a set of rules for the well being of the ecosystem).