I've been hacking Super Mario World on and off since 2006. I'm currently more than halfway through my current project in terms of completed Worlds, and while I have no intention of canceling it, I feel that it may be time that I try hacking other games, either once the SMW hack is finished, or when I'm in need of a side-project.
The main appeal of SMW hacking is that it's extremely easy, and this extends beyond the incredibly user-friendly Lunar Magic, which allows you to edit levels, palettes, graphics, and the Overworld map. Tools used to do things such as add custom music and ASM-based assets are also very easy to use.
Beyond Super Mario World, I've dabbled a bit in hacking the Genesis Sonic games, specifically Sonic 2, and have managed to complete a hack, even if it can be a bit mediocre. I've found SonLVL, the latest editor for these games, to be about as close to Lunar Magic in terms of user-friendliness as one can currently get for the Sonic games. Music hacking was also fairly simple, and I created most of the music in my Sonic 2 hack. Beyond that, though, there's a bit of a learning curve to other things, most likely because the Sonic scene has adopted split disassemblies as opposed to editing ROMs directly.
Prior to posting this, I tried SMB Utility for a bit, and while it seems pretty straightforward to use, SMB1 doesn't seem as flexible in terms of what can be done to a level. I have yet to discover how to add or remove objects or if that's even possible.
Here are some games I've thought of:
SMB3: I've kinda been interested in hacking this since playing Super Mario Bros. 3Mix.
Sonic 1: This MIGHT be easier over all than Sonic 2. There are more resources out there for it in terms of ASM hacks and the like.
Kirby's Adventure: I love this game, and KALE looks pretty user-friendly and Lunar Magic-like based on the one screenshot I saw.
Super Mario Land: I took a look at LandForger, and it looks pretty simple. Haven't actually tried it yet though.
Super Mario Land 2: This is another favorite game of mine. If I were to do this one, would MarCas or another editor be better for me?
TLDR: Which game should I try next?