In my opinion, Sketchup has a long way to go to be a viable construction documentation tool. There are many other products out there that do the job much better that are (nearly) as cheap.
I use the product for conceptual design and easy, quick renderings. So, instead of tweaking the minutae, I would rather see the product perform faster, with smaller file sizes. It is common for file sizes to quickly reach the 55MB range, and all manipulations within the file become a waiting contest, even with shadows off and faces set to monochrome.
It would also be an enormous benefit if files could be "cross referenced" into the current model, instead of importing as dead files. With this feature, the cross referenced file could be modified separately, and then all the references would automatically update.
So, it's like filling a container with multiple-sized balls. Get the big balls in first, and then the smaller balls can easily fit.