I understand what Platform goal will look like.
IMHO there're 2 aspects that really holding SketchUp back, which can't really be done in API level or plugins:
1.)No real curve, I don't know if we could really have some nurb in future.
2.)Display speed performances. SketchUp don't need any rendering baked-in anymore at this age.
And the strength of SketchUp have is it's simplicity and clean design. People can get started with very little learning.
And I see SketchUp is the best thing in 3D world, not even blender can have big market like SketchUp. Because while Blender is Open-source project, but it only apply for 3D industry. One who don't have knowledge about 3D can't use for their purpose easily.
Seem like the core philosophy of SketchUp is very Open-source, free as the meaning of 'freedom', especially like a CMS called Drupal. Drupal don't do anything best out of the box as a product (it's minimal feature for people to get started), but it API/hook system is supurb and embraced collaboration with other open-source projects and make it a very flexible platform. It position itself between web framework and product, it's not the best framework nor product. But People would find it can do a lot only when dig deep in and know how to use plugins and API, feel very SketchUp to me. And when other stuck to be CMS only, Drupal can and is expanding out to more market which make it very successful, their robust 'hook system' make this happened. It successful because both normal people and pros find they can use it and customized to their works. It can built blog, e-commerce, news site, intranet, social web, web apps, etc. I think this is how Trimble see SketchUp as a platform.
And I think there should be free and $500 vanilla SketchUp version as is. Take free stuffs and increse the price is not an options and right way to do it for this business age. Professionals can buy other well-enhanced versions at higher price range. I means those well-enhanced versions should be able to do more than current SketchUp with combination of free Ruby plugins, feature that is hard to do well with Ruby, or at least well-integrated to make it interesting and valuable. Things that superior than current SketchUp.
Also, I think it's already the time to do UI/UX improvements, seem keyboard shortcut and a static menu with lot of buttons is not the only way to interact in this age. SketchUp UI start to show its age. People need to move and remember less while still able to do thing as fast. Something like Customizable Pie menu on right-click and smart floating/transparent menu seem like a good alternatives for touch interface. At least, something like Lumion is feel very clean and easy to use:
http://youtu.be/D0uZb4Yl_VA
If Trimble value business partnership, there're so many businesses that already help SketchUp grow. Not only just software in Trimble PortFolios. Make better and deep intetgration with them and the platform can grow in so many directions quickly. SketchUp can play well and become another tool in the arsenals of many people, easy to added inot their workflow. So core SketchUp developer can focused on what they can do best, make the core platform robust, adaptable.
For example, a seamless back and forth workflow between SketchUp, Layout, 3d printing CAD, current CPU/GPU/Real-time rendering and animation softwares will suffice SketchUp as Archvis/conceptual design platform for 80 percent of market needed. That would empowered the current users and open to new job opportunity a lot in this niche (this dind't count the benefit of change management in design phases).
Also, it's very right decision that SketchUp embraced both Ruby and C++. SketchUp plugin ecology can't become so rich without Ruby.
And I feel the future is bright