Hi @mark.hutchinson
I also completely agree with you regarding the Dolibarr UI. I actually posted about this topic on the Dolibarr forum some years ago as well:
At that time, some people mocked me for the idea, which was fine. Looking back, I probably didn’t explain the idea in the best way, so I can’t really blame them. 
But after working for almost 10 years as a full-time Dolibarr developer, I can honestly say that I now have the confidence and experience to say that something like this is absolutely possible. In fact, with modern CSS/JS and a good understanding of Dolibarr’s architecture, creating a consistent modern UI across Dolibarr is not really a huge technical challenge anymore. The bigger challenge is probably doing it in a way that remains maintainable and compatible with Dolibarr’s existing functionality.
One relatively simple thing you or your developers could try, if you haven’t already, is a CSS stylesheet that is available online which can be added to the standard Eldy theme. It doesn’t completely transform Dolibarr, of course, but it does make the interface look noticeably more modern and cleaner. I experimented with it myself once just to see how far CSS alone could take it.
I’ve attached a screenshot showing what Dolibarr looked like after applying that CSS.
At the moment I’m working on a few fairly complex projects of my own (mostly for learning and experimenting, although they are becoming quite serious projects too
), so unfortunately I don’t have the time to contribute directly to your theme development. Otherwise, this is definitely something I would enjoy working on.
I really like the direction you’re taking, especially the idea of having the modern design continue throughout the actual Dolibarr pages rather than just changing the homepage/menu.
Best of luck to you and your development team — I’ll definitely be interested to see where this goes!
Thanks & Regards
Saikat Koley
Software Developer(Dolibarr)
Call/WhatsApp : +919903256573
Email : saikatkoley@hotmail.com
https://www.linkedin.com/in/saikatkoley/