So, there are some annoyances in "Boktai: The Sun is in your Hands!" that I have realized and think a good hacking could solve it:
1. The game is unfriendly for soloing 100%. Specially when it comes to Azure Sky Tower and the Wizard.
2. To resolve above: A hack that makes it so you get one different emblem each time you come across AST through and the Wizard Frame could be placed in a chest right at the entrance.
3. There is a random issue that kept happening to me with VBA-M, even with a clean ROM: The save data would randomly fail to load and be lost, as well as I'd often come across a "Failed to save settings", requiring me to boot up VBA CE to generate a save data that patches it. (had to rely on Save Stating to not lose my progress.
4. An addition of Lens EXP Counter would help a lot.
5. Change how Luna and Star lenses leveling works.
5.1. For Luna, it could be based on how many shots hits an enemy.
5.2. For Star, it could be based on how much you charge up to the Solar Bank.
6. Modify Delusion Forest's Shadow Puzzle to work with "Moonlight" too (but maybe invert directions and have Otenko mention how "you may have to flip your logic around, however")
7. Modify Kaamos punishment to simply disallow your entry into Sol City until you talk to Lita, who will tell you it's Kaamos and that she collected Solar Tree Dew for you to cure it.
8. Implement a Dark Boy Sabata mode through the use of the name Sabata, where you start off with the pieces for Gun Del Hel and the dark color palette. Of course, once you have beaten the game once.