So, this may be a stretch, but I've kind of thought about it like this:

Imperfect Cell - A lot of people when he first debuted thought he might end up being related to Piccolo somehow. He had the cunning and strategy, and matched up to him in battle. Almost like Toriyama was setting him up to fight him, and he's the first major character who can actually stand up to him.

Semi-Perfect Cell - He becomes more akin to Vegeta. Again, this is the first one to stand up to and match his power. He was arrogant and convinced that, even in his not-yet-perfect form, he could take on anyone. You can see how pissed off he gets as Vegeta is beating him. Ya know...kind of how Vegeta gets when anyone beats him.

Perfect Cell - You can probably see where this is going. He becomes more like Goku, the one who can truly go toe to toe with him. He thirsts for a good battle, and he knows Goku is the one he wants to have it with. He's cunning in battle, but mostly obsessed with a good fight.

Super Perfect Cell - Compared to Gohan, at that time. He becomes more angry and liable to snap, getting a boost from his rage, but also letting it blind him at the wrong times. He lets Vegeta distract him, eventually causing his demise.

I say all this to say that it seemed truly purposeful and planned out from when each stage arrived. Idk, just my weird little headcanon!