I don't agree at all. SketchUp is so much faster and more intuitive to use than anything else, that certainly for architecture - its core market. I'm not sure that anyone can argue that it isn't a professional tool. What did we have before it came along? Lightwave, Rhino, AutoCad, Microstation, Archicad, Blender, 3ds Max? Usability and intuitiveness of these things aren't close.
The difference between the free and Pro version is importers for other professional software, which is much more difficult to use and costs many time more. Simply importing geometry into SketchUp from these other programs because it is so much easier shows why it is a 'Pro' tool.
I have been using SketchUp since V2, and from V3 onwards, I haven't used anything else for 3d. I guess that's because I don't do much modelling of curved or organic forms though.
And regarding bugs, well the shadow thing is definitely irritating, but not a deal breaker. All software has bugs. My copy of VectorWorks 12.5 crashes almost daily. When I try to upgrade it to (hopefully) fix the problem, the upgrade aborts with the helpful message "Server says, Huh?" To make matters worse, the UK tech support guy didn't believe that any company would release software with such a stupid error message. That is supposed to be Professional software as well.
I agree with you about one thing though - Google should pay up or develop their own fix. Let's face it, it's not like Google are exactly strapped for cash is it?