Reimplement the Mega-Dragon
The Mega-Dragons in MM series are über enemies meant to be the ultimate challenge. The one in MM7 clearly isn't. It doesn't use the specific sprites made to it (using common dragon ones isntead), and the stats are even lower than a standard dragon (value overflow? Maybe they gave him maximum possible at the time and it was later lowered, causing an overflow?).
Here are the proper assets that need to be implemented: https://ulozto.net/file/qPbl8ZhYQ3Xn/megadragon-assets-rar