Vegeta has changed quite considerably over the decades. Although his general character is the same, his motives and his compassion has been dramatically different. Although he started to go past being a villain by the Namek Saga, many would argue that his change would actually begin the moment he became a Super Saiyan. Since that moment, developments have happened that further changed the character. Whether for minor reasons like the way he utilizes the form to his general personality overall.
Here are 10 ways that Vegeta has completely changed after he has become a Super Saiyan in Dragon Ball.
10 His Cockiness Has Been Reduced Dramatically
One of the biggest weaknesses that Vegeta has is underestimating his enemies. As a result of his arrogance, it got to his head and it resulted in many defeats. This is most prevalent during his time with the Androids and especially Cell.
Once he received the power of a Super Saiyan, he felt he was invincible. At least until he fought against Android 18 in which his arm was broken. Once he received his power-up of Super Saiyan Grade 2, his arrogance caused him to lose against Perfect Cell. Currently, it seems like these aspects as been reduced dramatically.
9 He Understood That There Is More To Super Saiyan
As brought up earlier, when Vegeta first became a Super Saiyan, he became incredibly arrogant and suffered a major defeat against Android 18. From this point onward, he was determined to improve himself. As he eventually realized that there are most likely ways to evolve the Super Saiyan form. This is shown by his eventual unlocking of the Super Saiyan grades and many more as explained later.
8 He Achieved More Forms Over Time
As a result of training and pushing himself constantly, he was able to continuously become stronger and stronger. Almost to the point of rivaling Goku prior to the introduction of God ki. After his defeat with Android 18, as mentioned before, he would gain access to the Super Saiyan grades. Later during the Buu Saga, he would unlock Super Saiyan 2, the same form that defeated Perfect Cell many years prior.
7 God Ki
Once Beerus became introduced to the world of Dragon Ball, the power scaling and forms started to change dramatically. After witnessing Goku's fight with Beerus with Super Saiyan God, he eventually got the chance to train with Whis. Getting more and more powerful and eventually achieving Super Saiyan Blue. Together with Goku, he was able to achieve plateaus that clearly surpassed many other Saiyan's barring the very few.
6 His Usage Of The Form Has Been Reduced
Somewhat a consequence as a result of getting many more forms, the so-called legendary Super Saiyan form became nothing more than a joke. While it is still a powerful form, Vegeta has utilized it far less compared to any other. Preferring to really only using this form to test someone out like Broly or to hold onto his own stamina, it is definitely not a form for power anymore. However, that doesn't mean he ceases to use it. Just as there are better forms he has in his arsenal.
5 His Connection To His Family
This is actually a very important thing not just for Vegeta's character but for the way the form is handled. When Vegeta first used Super Saiyan, he unlocked it out of a yearning to achieve what Goku had. When he got Grade 2, he mostly just trained by himself even though his son went with him. However, as especially shown when Beerus slapped Bulma, Vegeta's power and Super Saiyan 2 was enhanced in a way that rivaled Goku at Super Saiyan 3.
4 Humbleness
Vegeta has changed quite a lot since his time in the Saiyan Saga. Through his humbleness over the constant battles he fought and the beings he has met, he is now willing to train with others. Whether it's with Whis or the people from Yardrat.
As a result, his powers started to become far more diverse and his personality shift is also reflected in his power. A case in point is his willpower with Super Saiyan Blue Evolution.
3 Trains To Protect Others
Essentially a continuation to the previous points, Vegeta now trains not for himself. But rather to protect the people that he loves. This is shown with his training in order to deal with the Tournament Of Power. Or how he trains in the time chamber in order to defeat Goku Black due to what he has done to his son's timeline. Simply put, these gains in power are astronomical compared to the times where he trained alone in the Cell saga.
2 No Longer Pursues The Same Forms As Goku
For the longest time, it felt like Vegeta was consistently following in the shadows of Goku. He has gotten every Super Saiyan form up to Super Saiyan 2. However, even after training from Whis, he would receive transformations ala Super Saiyan God and Blue.
However, by the time of the Tournament Of Power, one of the greatest things that he has achieved was Super Saiyan Blue. A statement of his prowess of going towards a path that strays away from Ultra Instinct. Very much in contrast to the reason why he originally obtained the first Super Saiyan.
1 Spirit Fission
Easily the biggest development that Vegeta has had as a character. Perhaps even beyond his original notion of Super Saiyan, is looking beyond just using power. After his training in Yardrat, his use of Spirit control allowed him to be massively more powerful.
Essentially, this means that everything that Vegeta has learned through his experiences has essentially gotten into a complete 180. As he uses abilities that fans didn't expect to see. It is his mentality to look beyond just simple transformations that makes him even more dangerous than he was back in the Android saga.