Please note, though, this list is from someone who thinks MP2K2 is the second most useful program on his computer behind Excel. I love MapPoint, I just want it to be Super-Ultra FANTASTIC! Also, I use 2002, so I don't know how much has changed from there to 2004.
1. Ability to turn on/off everything independently. I want to turn on streams, turn off roads, turn off POIs, turn off city names, turn on zip codes, turn off state boundaries? It should be possible. Right now there's no way to get rid of city names/etc. even when you display a data map, I'd like to see JUST my data and nothing else. Random Mexican cities showing up when i'm plotting my sales info for the southwest is distracting, it'd be nice even to turn off an entire country/state.
2. Driving distance ONLY calculation, without route/map update. Will make my life much easier and my work much shorter. This is useful in doing optimization problems (my biggest use of MP), and could make MP more usable if you want to show map A, then calculate maps B, C, D, E... until you get a better route, and ONLY THEN update A.
3. Customizable map colors, I want the background black and roads bright, fluorescent green with cities in purple (not really, but I want it possible).
4. Ability to update built-in data, either through MSweb or by hand. I want to create a new restaurant type "McBob's" and be able to add in every Mickey-B's in the country, and have it integrated instead of adding new pushpin set every time. Essentially adding new P'sOI. This functionality would be incredibly useful for almost ever company that uses MP to find local distributors/etc. as they could add categories for whatever business things they use and have POI info by category for whatever piece they want to look at.
5. A better legend, maybe as a floating poly over the map or similar. To make a halfway-decent legend, I have to print-screen and photoshop it together, that's insane. If it's a part of the map though, it had better be removable.
6. Segment start/end points accessible programatically, so you can find the nearest POI from either end of a segment. I want to schedule my breaks ever X hours, and from wherever I am for the actual break (versus halfway between start and end), I want to find the nearest Mickey B's.
7. Smart(er) segments, don't tell me to bear slight right 75yds, turn right 0.1mi, bear slight right 100yds just for an exit, say"take I-95 exit 42". This is probably the hardest one, but it's been getting better for each version of MP i've seen.
8. Higher-resolution "Copy Map" sub-function, for presentations/print/etc. the map outputs at screen resolution, I have to "Save As Webpage" at 3500x3500 to get a decent high-res map. Even having the same feature with a "Save to Clipboard" option would be great.
9. Direct GPS/Lat/Lon support. Since MP2K1 there has been "alternate functionality" (thanks to that brilliant Gilles Kohl) to get the exact same information. Don't make me calculate lat/lon in my heinously slow VBA when MP MUST have the equivalent information in order to plot a point or show the location sensor. If it's against the license for the underlying data, point out that it's already available and relatively accurate, it's just not convenient.
10. Ability to plot as many "multiple symbols" as I want to. I wrote an app to do just that because 8 just isn't enough sometimes. It makes for a silly-looking map most of the time, but for some instances it's very helpful.
11. Transparency for symbols, to allow overlapping symbols to color-blend. Mostly useful for custom symbols, this is probably at the bottom of my wish list.
12. Same for territories, along with the ability to mark DISPUTED territories as such instead of simply ignoring them if there are duplicate areas assigned two different territory names. This could be very useful for mergers and acquisitions as a way to show territories in a meaningful way, and it would allow duplicate or back-up assignment more easily.
13. Direct linking to MS Access Queries or ODBC tables. I've seen some places that say it's possible, some that say it's not, i've done it with a CDL but not directly. No fiddling, no work-arounds, make it so "it just works".
Other stuff that would be nice additions but that I don't so much feel the need to rant about:
1. Map rotation, as suggested elsewhere, so the next route segment is always UP.
2. Better elevation data would be nice. Either a gradient or tighter topo rings to see that all of KS is not 100% dead-flat. Is elevation extractable? I haven't tried, but I don't remember seeing elevation for anything except a view, and that only gives you a different field-of-view.
3. Closest-point driving directions for everything, so I could calculate driving distance from DC to HI, even though it's obvious that I couldn't actually drive there. Right now it doesn't work because there's no ferry route, but there should be a way to indicate "You're on your own for this piece" in the event that map info is wrong and/or new paths are created after MP is released.
4. Interpolative results for zipcodes: since they're geographically oriented, if you don't know where 90210 is, it's probably right near 90209 and 90211. Yes, it can pop up a dialog box and ask me, but if i'm just importing a list of zips (like store/customer locations) i'm just going to do the same thing myself. Maybe a flag to distinguish between the two match types or an option for "best-match" versus "exact-match"?