Nice
Issues / suggestions:
1) When, in the Sounds Tab of Units.dat, you select a unit with ID > 105 (which only have What (Start) and What (end) sounds), and then select a unit with ID < 106, the selected unit have all sounds drop down boxes grayed out, except the What (Start) and What (end). You can still change the sounds using the number boxes, but not through the drop down boxes.
2) Is really Iscript ID 1 in Images.dat Unknown? Should it not be Scourge Shadow?
3) In Flingy.dat, could everything be moved two or three pixels to the right? "Halt Distance" is too close to the Group Box (see attached screenshot)
4) Why was the readme.txt removed in version 1.2 and 1.2b?
5) "Moved the "Restricts" property from the StarEdit tab to the "Advanced" Tab. Meaning still remains unknown." I assume that we do know that "Restricts" is not related to StarEdit? Or why else was it moved?
6) "Removed the unused flags for the Units editor StarEdit tab, for clarity purposes.(using them would force someone to alter the game engine anyways)"

For me, this somewhat goes against the very purpose of the program. We want every aspect of the files to be modifiable, and IMHO, this also applies to unused values. Can't you at least add in an option such as "Show unused values"? It doesn't even take up space that is needed

7) You wanted new features? As I've already said, the ability to compare a .dat-file with another. I have some old stuff I've worked with ages ago, and I have no idea what I've changed and haven't.... Such a feature would be awesome

8) May I ask why you don't want to add in multi-entry selection? I respect your wish not to add it in, I'd just like to know the reason... I think it could be quite useful, especially to test out the unknowns that are left...
9) The 'Doodad Info' still isn't lined up perfectly (See screenshot).

Thiese is veru importunt go fix olololol
10) If you want a new feature... Something like right clicking on the dropdown boxes with the strings from stat_txt.tbl where the text can't fit, and thereby getting the text displayed in a little pop-up box or something like that... I wouldn't use it, so I can't say I really care, but it could be of value to someone

11) As BST said, it would be nice to have <number> = <value> used with all dropdown boxes... The space becomes quite an issue then, I realize, but perhaps a smooth implementation for this could be worked out, possibly through a flag in the options dialog? Or using my previous idea with right-clicking on a drop down box?
12) Just coming up with ideas... I don't know if it is even a good idea to add it, but at least something to consider: Having individual hints for different values. For example, in Weapons.dat, if you select Explosion = Broodlings, you get a good description about what makes the value "Broodlings" unique in the Hint box. Of course, this could all be done as it is, but the hint-box would possibly be very difficult to read if throughout explanations of every value would be shown in the tiny box...