I think we've focused a lot more on relational support. For instance, on a detail page, you can view and edit all linked records, and add new ones inline: http://docs.fieldbook.com/docs/go-beyond-the-grid
Just an idea to share, from someone who's been building business apps using Knack's visual builder for the past year, I think a killer combination would be fieldbook's friendly UX for the database with a "marketplace" of front-end "plug-and-play" UI modules. So in fieldbook I would create and save views for the database with your current UI but then I could plug ready-made UI modules on top of that database view and then customize the front-end UI. Ideally these UI modules would be free or pay web-based or native.
I know it's extremely important to strike the balance of complexity, capability and UX so this area is notoriously difficult to tread but I think whatever solution does it right without sacrificing customization extensibility is going to win big!
Fieldbook looks great and I hope it keeps getting better!
Eve's already been mentioned here, and Chris' lecture at Cal was really interesting from a UX perspective. I'm sure you've seen it but if not, go watch it.
The spreadsheet model is fairly intuitive for the end-user. He and Rich Hickey both are pretty convinced that a Datalog-esque query engine is the way to go. 20 years ago, Lotus' Improv's model (where you separated the data manipulation from the data type constraints) was way ahead of its time and guaranteed so much more internal/referential integrity than 1-2-3. Modern-day Quantrix is probably the closest you'll get to it, used pretty heavily in niche finance.
MSR puts out some interesting work on the PLT behind alternate spreadsheet grammars[1] which are quite interesting too. Other than the obvious issues (ETL[2], ACLs/RBAC, presentation/extensibility) MSR has put out quite a few interesting papers out there. This is a very interesting problem domain to say the least. I've developed up-to-the-Pareto-point for this in the past for clients and if you get it right, it's a license to print money.
[1]http://research.microsoft.com/en-us/um/people/sumitg/pubs/pl...
[2][both conventional a la SSIS and Informatica, as well as a Pipes-esque query; a premium feature you could easily charge into-the-Oracle-rates would be a Pipes-esque service with an SLA. I've been in enterprise consulting long enough to know that whether you're Ingersoll Rand, Haas, an REIT or Cravath, sanitized, guaranteed data is worth a lot, integration is worth even more.
I think we've focused a lot more on relational support. For instance, on a detail page, you can view and edit all linked records, and add new ones inline: http://docs.fieldbook.com/docs/go-beyond-the-grid
We have a full-fledged query UI: http://docs.fieldbook.com/docs/focus-on-relevant-items
And we have a grouped view (think Trello meets spreadsheets), which is great for any kind of pipeline/kanban view: http://docs.fieldbook.com/docs/track-a-workflow