I'll refrain from passing judgement on that since alttp looks significantly more complicated... at least in terms of graphics... What specifically do you find wrong with it, is the interface just too arcane or something?
Foreword: I use HM on a daily basis so I take the oppurtunity to bash it when I can.
Besides all of the bugs that result from the program not being designed to properly deal with the data structures of the ROM (something it should have more extensively expanded and rearranged as soon as you began editing the ROM) most of my complaints can be chalked up to it being unfinished, abandoned and having an author who is too much of a *insert insult here* to allow people to finish what he started (no source code). The program has a ton of features to edit nearly
everything in the game but half of them are "use at your own risk" or "never use" because they are broken/unfinshed.
Let's say you want to totally redesign a room. Most people would probably want to empty the room first and then refill it. Never do this with HM unless you want to destroy your ROM. It's too stupid to do something like this. If you want to totally redesign a room the best thing is to resize all of the objects that can be resized to their smallest and then pile all of the pieces in one spot and pick things from it one at a time. If you don't want to use the objects that the room was composed of you have to highlight an object, right click and then choose what you would rather it be. This opens a window with all of the different pieces in it but the window doesn't work with the mouse wheel so instead of scrolling easily you either have to click up or down, drag the bar on the side or type in the number of the piece you want (there are hundreds). Scrolling with the mouse would make this much less annoying. When you have used up all of the existing pieces you can safely add a few, but not many. If you have some left over it's probably best to only remove a few and leave the rest somewhere out of visibilty if you have the option.
Let's say you want to add a door in one of the rooms. You choose BG3, left-click anywhere, choose "insert a door", navigate the same stupid window desrcibed above (no mouse wheel support) and when you make your selection, the door will appear, but in a random spot. To move the door to different positions that are predetermined you MUST USE THE ARROW FUNCTION OF THE NUMPAD ONLY!!!!!!! YOU CANNOT USE THE STANDARD DIRECTION KEYS!!!! My laptop does not have a numpad so every time I want to add or move a door I must open a virtual "on-screen keyboard" and move the doors with it. STUPID.
A few things I would suggest to make you editor all that it can be:
-Have people use it and give feedback so you will know what you are overlooking or what can be improved upon (AND FOR BUGS!!!).
-Take the time to finish it and if you don't, allow someone else to. If even a half-assed editor exists, no one is going to take the effort to make a proper editor because it takes less effort to use a buggy, unfinished editor than to program one yourself. (I don't wanna hear about Black Magic)
Closing remarks: Hyrule Magic is so shitty that to make the best use of what the game itself
has to offer, your best bet is to design one dungeon at a time in separate ROMs and then when finished, cut and paste the data from each into one expanded ROM with a hex editor and then rewrite a bunch of pointers. Despite there being many people who want to hack this game, there are so few existing hacks because a person has to be insane (like me) to do all that must be done to finish a functioning hack with this program. You have to spend weeks or months learning exactly what you can and can't do with it: what is safe and what will destroy your ROM. Even then you will be required to fix bugs with a hex editor.
Well, I don't know if that will help or if I am just blowing off steam. LOL