I would guess it's because there are alternatives.  Graphics can be easily edited with a tile editor -- but you can't trace without a tracer or debug without a debugger.  So making a full combo graphics editor built into the emulator would be low on the author's priority list, I'd imagine (lots of additional work for something which can already be found elsewhere).

Plus honestly... I always thought NESticle's runtime CHR-ROM editing was more of a gimmick than an actual tool -- since it didn't have a lot of the basic features available in any generic tile editor (view the whole ROM, copy/paste, multiple files open, etc, etc).  Though I guess seeing the changes in real time can be useful....


Anyway -- I'm sort of working on/off on an emu with bbitmaster (of FCEUXD fame) which, if goes according to plan, may have such a feature -- but less stupid.  Although I shouldn't count my chickens yet, as we seem to have constant schedule conflicts and can never really connect at a time when we can both work on it.

Well, I think that the being able to edit them in real time allows you to get access to normally compressed and hard to get to graphics.

It would be interesting to see that idea taken and improved upon, like you said, having a blank page or so to copy, paste, rearrange tiles on.

CHR-ROM isn't compressed or hard to get to.  CHR-ROM is always neatly bunched together after all of the PRG in any given .nes file (provided the desired game uses CHR-ROM).

Compressed or scattered graphics spells CHR-RAM -- which, if you recall, NESticle didn't support.  Sure you could edit them at runtime in NESticle... but fat lot of good it did you because you couldn't save, and your changes would be "forgotten" as soon as the game redrew its tiles.

Very very basic CHR-RAM saving could be implimented I suppose -- but only for games which simply copy bytes from PRG-ROM to CHR-RAM directly -- and even then, it would kind of be a pain in the ass (the 6502 could record where in PRG-ROM the last LDA/LDX/LDY instruction read from -- then on writes to CHR-RAM, record where each byte came from).  Plus this might not be reliable all the time, and there's always the possibility of a mistrace or something and the emu saving over PRG that has nothing to do with graphics (potentially totally destroying your ROM in the process).

However this will only work in the simplest of simplest games (ie:  games easily editable in any tile editor).  Compressed graphics and runtime-generated graphics (eg:  the "The End" drawn out at the end of Final Fantasy) could never be supported in this fashion.  Sure, a tile editor could DRAW the tiles so that you can see what they look like -- but then again PrintScreen or a screenshot feature does that just as nicely.

Like Disch said,
nesticle just doesn't cut it any more.
 
You could save your changes only on Roms that have vrom or chr-rom like smb1, not chr-ram like say marble madness i have always wanted  To make an hack of it called mario madness where mario replaces the marble but if you open it in tlp or yychr you can't see the part that Needs to be changed because the graphics are compressed in the chr-ram until the game loads up the to that part of the game where you See the marble i was able to put mario inside the uncompressed chr-ram with yychr and then i could load it in nesticle and see the part Where i wanted to copy and paste the mario marble but was unable to do it because one there is no copy and paste and i could've change The compressed graphics so i could find them in yychr but there noway to save it because it uses chr-ram. Anyway i hope they do make a Newer emulator that would support on screen real time editing and copy and paste would be nice too but in most cases it is not needed.
I would be happy with one like the one nesticle uses with the added ability to edit Rom's with chr-ram and save it too.

Another ideal would be to make an emulator that has the ability to create an ips patch for an loaded rom and export it to and external file for later use so then if you changed something inside the one emulator and wanted to play it in another emulator you could just apply the patch And play it the same way it was in the other emulator. I know there are emulators that will apply patches but none of them will create a patch.

Yes that would work, But I still think that it would be nice to have an emulator that could make the patch for ya,
Because if you make certain changes in an emulator they are only in effect while the ROM is loaded,
And if you unload it all is lost if the emu could create an ips patch on the fly you could have the same effect everytime
You load the ROM or even in another emulator,
And you could in theory keep all your changes no matter what emulator you load the ROM with.

I knew that nesticle could save  but I didn't think there was another emulator that did,
I have fceu and fceu sp but not fceuxd i give it a try thanks.
Also i think that the method that nesticle uses for saving changes is similar to ips patching because it does patch the vrom or chr-rom,
But I am not certain about it.

Well another thing that I  have used nesticle for I haven't seen in other emulators either is if I want to make table file.
If the ROM is supported by nesticle I can look at the pattern viewer,
And get the hex codes for the entire font in the ROM thus making table files easier to make,
Most of my font hacks where done by using nesticle for this with the external use of an hexeditor,
But I have been looking for another tool thats more up to date,
And as far as i know there isn't even a tile editor that I know of that will give you the exact hex codes for the entire font.
Maybe a debugger can but i do not know how to use one at all and don't really want too because learning it is over my head.