Thanks for the feedback, @lenaMK. And sorry for the bad timing!
AI is entirely optional; you’ll be able to teach without it. We think AI is a helpful tool for learning (when used judiciously) but completely understand any reservations you may have.
We’ve no plans to implement non-code cell modes (data table cells and chart cells) in new Observable. While these cell modes were convenient and arguably friendlier for some users, they were extremely limited and added a lot of complexity to the user interface and implementation. We found these cell modes to be functional “dead ends” for users rather than helpful stepping stones to learning. And these modes saw relatively little use overall. Observable is a computational notebook and by nature a code-centric tool. Especially with AI (optionally), we think it’s better to embrace code. And we think this focus on code and parsimony in features makes Observable better — though again, sorry for the disruption.
That said, SQL cells retain a lot of the functionality of data table cells (just with SELECT * FROM table). We haven’t yet shipped an improved summary table for SQL cells, but we’re working on it and it should be available soon. This will provide visual column summaries and visual filtering for tabular data without writing code (other than SQL). We think the summary tables are super useful so it’s worth the effort; meaning, the point of the summary tables isn’t to eliminate the need for code, but to give you something better than what you can practically write with code.
The way to exit a chat is the same as exiting a notebook: you choose to go somewhere else. 
You can go back to your workspace using the workspace menu, create a new notebook, etc. Perhaps we should add a “back to workspace” button next to the workspace menu. It’s probably worth the space given how common this action is even though it’s redundant with the menu.
We haven’t yet implemented linking to cells. Notebooks 2.0 have slightly different structure since we’ve adopted vanilla JavaScript and TypeScript, so we’re planning on supporting both links to Markdown headings (the anchors are already present using markdown-it-anchor via Notebook Kit, but links don’t yet work due to the iframe sandbox) and to named top-level variables (which is roughly equivalent to cell names in Notebooks 1.0).
The dataflow panel (a.k.a. minimap), find panels, and history panels aren’t yet available in new Observable, but we’re working on it and they will be coming soon. You can access version history in old Observable for now. Similarly new Observable doesn’t yet support editing collections, nor search, so you’ll need to use Old Observable for that for now. Though of course you can browse public notebooks and collections and authors to get inspired.
We’re working on building out more features as fast as we can, and we appreciate you letting us know which features are most important to you as that helps us prioritize (as well as feel some extrinsic validation)! Thank you!