There's a slight misconception held among the Dragon Ball Super fandom regarding the nature of Cell Max. Some people believe that he wasn't as powerful as he could have been and that the Z Fighters didn't fight the Bio-Android at his full power. The assumption is that if Dr. Hedo had been given the time to complete him, he would have been much stronger.There is some truth to this, but not in the way many people think. While the full range of Cell Max's capabilities was never explored all the way, that doesn't mean he was kept from being incredibly powerful. One could even argue that, in a way, the series showed Cell Max's full, unrestricted potential.
Could Cell Max Have Been Stronger?
Part of the assumption that Cell Max could have been stronger comes from his resemblance to Semi-Perfect Cell from Dragon Ball Z. In theory, this would suggest that Cell Max also has a Perfect form beyond what was shown to audiences. The concept for this theoretical Perfect Cell Max has been drawn by many fan artists across the internet.
However, Cell Max doesn't have a Perfect form, nor was he supposed to gain one. According to Dr. Hedo, Bio-Android's physical body was all but complete. This means that the Cell Max audiences were shown had no other form, nor was he supposed to gain another. Physically, he was as strong as he was ever going to get.
The only thing Cell Max that was missing was his mind control programming. This presumably would have allowed remote commands to be given to the android with the sound mind of a seasoned martial artist. However, since he was forcibly activated before the programming could be implemented, he simply went on a rampage; he showed minimal combat proficiency and instead relied on throwing his weight around to win battles. This clearly was sufficient, as it required the help of every available fighter to stop him, but he might have had a better showing if he were a more focused fighter.
There's also something to be said about Akira Toriyama's description of Cell Max. According to him, if the android had been completed as planned, he would have been stronger than Broly. Since he was forcibly activated, he instead became an uncontrollable monster. This description is a little vague, but it seems to suggest that, if Broly and Cell Max were both left to go berserk as they are inclined to do, Broly's brute force would eventually overpower that of Cell Max, allowing him to win the fight. If Cell Max had some control over his fighting, however, he might have the combat efficiency to outmatch Broly.
Were Dragon Ball Fans Cheated Out of a Better Cell Max Fight?
The difference between a controlled Cell Max and an uncontrolled one isn't so much one of strength as it is how that strength is used. In this regard, whether the Bio-Android's actions were being controlled or not, the spectacle of watching him fire energy blasts and blow things up would have been the same. That just leaves the question of whether seeing Cell fight more like a martial artist than a giant monster would have improved the battle.
It's also important to remember the point of making Cell Max a rampaging monster, unlike his predecessor. This incarnation of the Bio-Android was likely written as a third-act villain to give the rest of the cast a common enemy to fight against. Thus, even if things had initially according to Dr. Hedo's plan and the mind control program was complete, Cell Max would have probably been made to go wild eventually. Having him activated prematurely was the ideal way to trim the narrative fat. Perhaps the manga will show this scenario with its extended story.
With all that said, seeing a completed Cell Max in action is still an intriguing prospect. With the idea of greater potential dangled above the audience's heads, one can't help but wonder about what could have been. Open-ended power scaling questions like these can be frustrating, especially in shonen battle anime like Dragon Ball.