If you unpack the packed.pak file into the same folder and "remove" the packed.pak by renaming it to something not ending in .pak, is there any problems excluding validation and updating just creating a new packed.pak? i haven't seen any problems, but i'm wondering just in case
I've replaced mine before. I ran all the assets through PNGgauntlet, then repacked and replaced packed.pak. Everything worked fine. Of course that file has been replaced since(updates). So it isn't hardly worth doing. But technically you can. It makes far more sense to just build mods that change what you want changed.
You'll have a minor error like "unrecognized file packed.pak.no in ./assets/" but that's fine otherwise. You could just move it to another folder too. It makes sense anyhow to move it to where you unpack things. I personally unpack in a folder the game isn't looking at/won't use. I also copied asset_unpacker.exe and it's dependencies into the \starbound\unpacked_assets\ folder I made for that purpose. Early starbound used loose assets like it looks like you intend, but they're too tempting to edit directly instead of modding properly. I expect the support headaches from this contributed to their decision to pack files. I just wish they used something more standard... something supported by 7zip(etc) instead of their ever-changing proprietary formats.
i unpack the packed.pak so i can edit it freely and use it. new update rolls around: unpack.bat is run immediately (unpacks it quickly)
Nah I just copy/paste it. I collect the old packed files anyhow in case I want to compare new to old. Comes in handy. If I wanted it instantly ready, I guess I could hardlink the file into \starbound\unpacked_assets\ I do leave a terminal open with this folder as the current directory. .bat file nothing! I can click <up> to scroll through previous commands, edit them if necessary. But I'd rather not hardlink, since I copy/paste, unpack, rename, move to a different "archive" folder. Of course you are under no obligation to do things as I do.