Thanks for your feedback, this topic is on lots of people's mind at DO.
Part of the reason it isn't seamless already is that it's a difficult thing to get perfect. The different properties have very different requirements.
For example, the Community's objective is to solve developer's problems via teaching. We want it to be equally useful for people who aren't using DigitalOcean products. Community gets lots of visitors on mobile phones the control panel doesnt, so it's responsive while the control panel is not. Community is first and foremost a content site, whereas the control panel is an application, so we optimize for different things.
Another part just comes down to Conway's law [ref] As the saying goes:
organizations which design systems ... are constrained to produce designs which are copies of the communication structures of these organizations.
DigitalOcean is not immune to this. As we have grown (now 500+ employees!) it is impossible to have a single design and development team building everything.
But we're always working on making the experience better for everyone! For example, recently we update the nav so that when you're signed in on community, the utility nav at the very top will always contain quick links to most commonly requested other sections of DigitalOcean.
We're also working on Universal Search with the intention of helping users quickly find and navigate to content across all sites.
Are there specific areas where the experience is disjointed, do you have suggestions on how we could fix them? Keep your feedback coming, the more specific the better. We're always looking to improve.