1.) I wish I could easily search for files by their name. That's the ONE thing. It's not currently being solved in 10.4.1. (Nor are the other Spotlight gripes like Cmd-"f" showing a _really_ strange default choice that is _not_ user changeable...)
2.) I wish Mail.app's icon would show the count of unread messages instead of just showing the unread messages in my inbox. My goal is to use rules to filter MOST of my mails, i.e. the inbox only gets - basically - unwanted mails from contacts I don't know. (All others are automatically sorted.)
3.) Focus on professionals. This is quite a "soft" wish, I guess, and it might be better aimed at 10.5 than at Tiger's little updates. What I mean is: Enough of those rather small and "fun" improvements already, Apple! Enough of those nice little filters for iPhoto, gadgets like Dashboard, convergence of iLife applications. I want a Finder that works, I want a search tool that works, I want you (Apple) catering to graphics designers, I want a Font Book that actually works (it needs to be MUCH, MUCH better).
If I look at the history of Mac OS X, I think the biggest worst thing Apple has done to us users and developers is: The Finder. It was unbearable in DP4 (I didn't look at DP3 and earlier) and the Public Beta as well as the first release version (10.0). Apple, it seems to me, has not acknowledged this ever since. They've started to bring some features back from OS 9 (labels, spring-open folders) - but only half-heartedly. (You can't choose the colours of the labels yourself, spring-open folders misses to be predictable enough.) But they have merely started to fix things like icon spacing etc. On the other hand, they seem to have had enough time to implement things like smart folders, burnable folders (10.4), inline search, Brushed Metal (10.3) as well as cosmetic changes to Aqua. While I don't say those were not important, I think - I almost BEG - it'd be important to fix the Finder. I actually think about demonstrating in Cupertino, should Apple not consider fixing the Finder a top priority for 10.5. But now I'm majorly off topic, ain't I. Sorry for that...