Some really big codes doesn't fit. Something like max 500 codes would be great.
Instead of just increasing code counts, VBA-M should include more intelligent way of handling cheats. Some of the more complicated cheats are simply impossible to implement just by GameShark codes because they rely on freezing the addresses dynamically assigned by pointers, or some codes only function when other variables are set to certain values. MAME already have something similar in the form of XML cheats, but nobody seemed to bother to document how the XML syntax so that existing cheat databases can be reused on other projects.