Hi there,
I'm currently on a project which is for mobile, using in the region of 30* separate sprite collections. Due to the nature of the project, this is only likely to increase.
Our sprite organisation has not been based on "what gets used simultaneously", so it's sub optimal. Entire sprite collections may be loaded just to display 1 sprite from them. There might be 8 sprite collections loaded for one scene, with the scene only referencing one or two sprites from each collection (I exaggerate, but you see our problem!) . Not normally an issue, but we're on mobile, and thus have to be extra cautious about hitting iOS's magical memory "fuck you" threshold.
So, we have to reorganize our sprites in order to minimize sprites which aren't being used at any given moment. This is mostly easy for us to do since our game is very menu heavy, so our menu screens seem to split into collections quite easily.
My question/suggestion for a feature is to have some kind of run time analysis tool which tells you what sprites are being used right now, and from what sprite collection. Also, something to tell you what percentage of each sprite collection is displayed at once.
I'm going to have a stab at it in my own bad way, by running through every camera, and every sprite, and doing an "is visible" check, and then putting a little "check!" mark against each sprite collection to say that it's used, and just have a look at that data in the inspector. Pretty slow, but it's analysis so it doesn't have to be in the release. Maybe there's a better way which hooks more directly into tk2d code? Perhaps you could suggest a better approach to the meta-organization of sprites based on common useage.
*2dToolkit: we love you!