I was under NDA for Aperture 1.5 while I worked on FlickrExport, but I'm not currently under NDA for any in-development version. I'd love to be, though!
Also, I'm going to skip the justifications for why I want Aperture to be faster. Everyone writes that in an Aperture wish-list, but I always want everything on my Mac to be faster.
GPS Metadata Editing
I get this one all the time from FlickrExport users and I'm bored explaining that Aperture doesn't allow modification. I want it too.
Ability to lock versions
I'd really like to be able to lock a version to prevent future editing. Once I've processed an image, I want it to stay that way without having to render it to a TIFF file. I often pull a version into some other folder or light table and then get an idea to tweak it slightly. Then I wish I hadn't re-tweaked my tweaked image.
Comments field on Projects
As I wrote earlier, I use a lot of projects and they've sort of built up into a photographic record of life. I'd like to be able to associate some text about a project with the project itself.
Better Handling of externally processed RAW Files
What I mean by this is better handling of RAW files that were first processed in another app. If I take a RAW file, open in in Adobe Camera RAW and make a Photoshop file out of it, I want to be able to take both of those into Aperture and have Aperture treat it as if I had imported the RAW file directly, made a version and opened it in Photoshop.
What happens in Aperture 1.5 is that you can import the PSD file, but it's treated as a distinct master file and, if you then do "Open in External Editor", Aperture renders your Photoshop file to whichever external editor format you've chosen and sends that to Photoshop. Daft!
Allow the use of Adobe Camera RAW instead of ImageIO
I don't know if this is even technically possible, but it would be absolutely superb if Aperture 2.0 would allow the use of Adobe Camera RAW to do the initial RAW decode, rather than relying solely on the built-in ImageIO framework on Mac OS X. This would provide two immense benefits: firstly, Aperture would get support for new cameras as soon as Adobe had it and secondly it would take away all the debate about whether Aperture or Lightroom has the best RAW decode. Like running Windows on your MacBook Pro, Apple's strategy should be to have both and let the competition be the restricted choice.
Personally, I've had few problems with the quality of Aperture's ImageIO RAW decoding, but I would like to see Aperture support new cameras faster (if only so I don't have to keep reading it as everyone's #1 criticism of Aperture - as if people get new cameras every week!). I would, though, also like to see Aperture support a broader range of RAW formats, such as the Ricoh cameras, the Canon G series and the Sigma DP-1 - because whenever that thing ships, I'm buying it.
Expand Stacks into Grids
Stacks are great, but the concept is already stretched almost to breaking point. If I stack images, then open one in an external editor, then make another version of that image, then edit that one, you end up with stacks within stacks. Aperture's concept of Stack Picks is a clunky way around this.
If stacks were expanded to grids, one could group images horizontally and then versions of one image could be like 'vertical stacks'.
A Keyboard Shortcut to "Move Next" while focus is in a textfield
This one drives me nuts in Aperture 1.5. If I want to edit, say, the IPTC Headline field for several images (that's the field FlickrExport uses for Flickr titles), I have to click an image, click the field, type, click the next image, click the field, type, click the next image .... and so on. Too much mousing, and Batch Change Metadata doesn't help at all, because each version will have different contents in that field.
Lens Model Metadata
I'm just nerdy like this, but I'd like Aperture to read the lens model from the EXIF maker notes and complete the metadata for that. I'm optimistic that this will happen because, on Leopard, the ImageIO framework that Aperture uses for image handling now supports extracting that metadata from image files. It didn't support that on Tiger.
A visual warning when soft proofing is on
Soft proofing on screen is a great feature, but the only indication that it is in operation is a check mark against a menu item. I would really, really like it if Aperture 2.0 had some kind of visual indicator on the main window that soft proofing was engaged. Too often I've left it on by mistake and edited images in a weird way.
I love that the Loupe can be summoned by holding down the tilde key, but I think that concept should be extended to the adjustments and keywords HUDs. If you hold down H, the HUD should fly to your cursor.
More than two metadata overlays
I make a lot of use of metadata overlays on images, both in the grid and in the main viewer. It's a bit limiting that you can only have two sets for each. I'd like to be able to take any metadata view that you can configure and have it (optionally) available as an image overlay. I wouldn't want every single metadata view available, but more than two would be great. I imagine that Shift-U and Shift-Y, the keystrokes that switch between each configured overlay could be extended to cycle through the possible set of overlays.
Searching is pretty powerful in Aperture, but I would like a way to save search configurations that I could recall. Setting up a smart album is fine, but Smart Albums have a defined scope - they're limited to the images in their container. I'd like to be able to go into any project or folder and immediately pull up a pre-configured search for "all images over 2 stars with a focal length of 100mm and the keyword 'April'".
Support Photoshop Plugins
I've been using Imagenomic Noiseware Professional and it's just an amazing, amazing tool. If Apple could somehow figure out how to support the Photoshop plugin API, I would be a very happy person, just for the ability to use Noiseware.
Steal the Split Toning, Clarity and Vibrance adjustments from Lightroom
I really like these adjustments and having to round-trip to Photoshop just to do them is slow, boring and wasteful of disk space.