I have some suggestions that I thought I'd run past you splinterz and see what you thought. Make of them what you will.
The first suggestion is (hopefully) relatively minor. The "Group By" drop down box can list 10 categories, which I think back in the day used to be all of them. But there are now 16 categories, which necessitates much scrolling up and down over the course of a DF session. Would it be possible to make the number of concurrently displayed categories (ie the size of the drop down box) equal to the total number of categories?
The second suggestion is a bit more beefy. I put a fair bit of effort in to managing the highest moodable skills on all my dwarves to ensure I get the maximum number of artifact weapons and armour, and the minimum number of artifact toy forges. With around 200 dwarves, it's a big job, but it's made a lot harder because I can't directly tell who has already had a mood from the main view.
For example, I have twelve dwarves in the "Metalworker" custom profession and I want to set three of them to do metalcrafting, but I don't want any of the three to be ones who haven't yet had a mood, because the experience gain in metalcrafting skill could overtake the current highest moodable skill (say weaponsmith or armoursmith) and result in an artifact goblet. The only ways for me to tell who has already had a mood that I know about are to change Group By to Highest Moodable Skill, multi-select all the dwarves who have already had a mood, change back to group by Profession, and then enable the metalcrafting labour on the highlighted dwarves. Seeing as the multi-highlighting is lost as soon as I click to enable a labour, I have to go through the whole process again and again if I forget which dwarves are highlighted or there are a lot of dwarves to set labours for.
The other way to tell is to right-click on each dwarf in the "Metalworker" custom profession sequentially and select Show Details, scroll down the Skill list until I find the one that's highlighted in blue, hover the cursor over it until the tooltip appears and tells me if they've already had a mood, and then close the Details box. This gets pretty tedious pretty fast for lots of dwarves.
If I could tell who has had a mood from the main grid view that would save me so much time and fiddly effort. It seems to me the best solution would be a new column, "Highest Moodable Skill". It could re-use some of the icons from the "Current Job" column to indicate what is the current highest moodable skill, or the "No Job" icon to indicate there has already been a mood. An added advantage of this method would be the you could sort on this column.
Another way I can think of to do it would be to put a coloured border around the labour cells for the highest moodable skill, in the same way as for "Pending Changes", but with different colours. Say a blue border around the cell for the labour that is the current highest moodable skill, or a green border if they have already had a mood for that skill. The red of a pending change would take precedence over either of these. This method would not allow sorting.
A couple of minor ancillary suggestions are in the Details of a dwarf under Skills to change the highlight colour of the highest moodable skill if the have already had a mood (so you don't have to hover for the tooltip), and to add text to the header section of Details (around the Name and Age section) to say "Creator of <artifact name>" in the same way as the [v]iew - [g]eneral header section of DF (though this last suggestion might be a bit tricky I would guess and is not really important).
Anyway, just thought I'd make some suggestions that would make managing Highest Moodable Skills a whole lot easier. Look forward to hearing your thoughts, and thanks in advance for considering them.