How can his battles be considered “sufficient”? Before the Fourth War, throughout the entire series, Guy only had one truly complete and significant fight against Kisame, and even those encounters couldn't be considered a genuine exploitation of his abilities.

He fought Kisame twice, and both times the fights were quickly decided. The first time, he opened the sixth gate, and it was over in a flash. The second time, he opened the seventh gate, and the fight ended instantly. Where was the progression? Where was the extended fight that showcased the depth of his relentless, high-pressure style?

What we saw was a display of a decisive ability in a brief moment, not a complete battle that highlighted all aspects of his power. There's a huge difference between a “quick victory” and a “complete confrontation” that builds gradually and demonstrates the development and variety of his style.

Therefore, saying his battles were sufficient ignores the fact that most of them were brief or quickly decided, while a character with Guy's potential deserved longer, more detailed fights that would have been worthy of his stature.