This is, of course, just my opinion.

1. Search within a document.

I can't stress enough how frustrating it is not to be able to limit searches to within certain documents. If I want to find something in Tomb of Annihilation, I have to use Global Search, which returns global responses, which means I have to sift through them all to find the ToH ones, including all the forum responses which I have no interest in. Even limiting it to Compendium still doesn't help this issue.

As an addendum to this, often I'll be searching for something and it will return no results, even though I know it is in the document. Searching for things within ToA, for instance, has returned dozens of results for every other book but ToA.

2. Contents links on every page.

Having no contents links within each chapter is incredibly annoying. Flipping back and forth between the contents page and other chapters or having to have the contents page of a book constantly open in its own tab means dozens and dozens of extra clicks and tab swapping throughout a session. These clicks and tab switches would be unnecessary by simply having the contents links in the floating sidebar of every chapter. The contents page really isn't that large and it would go a long way towards making it easier to navigate a document while at the table.

3. Links within documents.

There are hundreds of link opportunities missing from documents. ToA alone has so many places where a link would greatly improve the ability to use DDB at the table. Any time the text indicates that you need to reference something elsewhere, there needs to be a link to that location. This is the most powerful aspect of having a digital service and it's by far the simplest and easiest thing to implement in such a service. There really needs to be a lot more linking going on in documents.

These are just the three main things that I find I am constantly butting up against as I'm trying to use DDB at the table. The lack of these things slows me down and frustrates me when using it. Any time I have to spend time searching for something, is time I'm not spending concentrating on the game and the players.

I agree with all of these, and #1 in particular has been causing me some frustrations.

Great list. The ToC thing is my biggest frustration right now, particularly when I'm digging through adventures to mine content for my games and often have to do a lot of going back and forth. Opening everything in tabs kind of helps, but I'm sure we could have a more elegant solution. 

Agreed on all 3 points.

Add my vote to all 3. However, I'm willing to bet the DDB team already has it on the To Do list. Probably just a matter of where that is on the priority list.