For one, he'd be a far better written character than his overly arrogant, infodump loving canon self.
As for how this affects the plot, it would mean Piccolo and the rest are absolutely unprepared for whatever Cell can do. The Rosat would still occur since beating #17 and #18 was the main reason for this and without being keyed in on how Cell would achieve his Perfect form, Vegeta kills Cell. Even if Cell tells him and Vegeta lets it happen, it just means the timeline goes on as normal. If the former happens then Kuririn requests #17 be revived once the new DBs are usuable and 7 years later Dabura is killed by either Goku or Vegeta, with Goku's Otherworld training not occurring and thus not making the gap great enough Vegeta chose to get possessed, and Babidi's plans are foiled. Super doesn't have much major changes overall.
What would be a major change is that Present Cell would continue to develop and have far greater strength due to the computer not halting it's job due to seeing how much of a leap in power Goku had made. Whether or not the computer would make him capable of growing into a major threat is highly debatable. Either Cell is fodder quickly disposed of when he appears or the data from God tiers would lead to him soloing the cast.
