I don't know if this has been brought up before, but it would be a great time saver to be able to deal with tags in a new tiddler with arrow keys and carriage returns.
For example, start typing a new tag. The auto complete list pops up. You arrow down to the tag you want and just hit enter. For new tags, just type the word and hit enter, rather than having to click on the add button.
I think it would speed up my note taking a great deal.
Andy