The original Ben 10 won the heart of many kids because it introduced a new unique way of writing super hero stories just like how some Japanese mangas do not feel shounen at all, in the case of kimetsu no yaiba, attack on Titan etc. The original was great and went well and could have ended there perfectly. But there was a successor. We all believed that a kids show could not transition into a darker theme. But guess what it did and proved us all wrong.
Alien Force came with a new arc which saw our characters mature. Unique villains were introduced into the system and a bigger cast emerged. Ben's love interest was deeply invested in too. Everything was perfect and it could have ended there but nope, another successor emerged.
Ultimate Alien begun with a bang! The first episode fed straight into one of the franchise's biggest and wildest arc; Agreggor. This meant that even though we wanted AF to end the Ben 10 franchise, we were sucked into a great new arc that changed our minds in UA. Ultimate Alien improved the battle scenes to an overpowered level which for so long Ben deserved. Most of his fight scenes in the previous enabled villains victorious with plot armor since it was a show meant for the younger. But now Ben fights and puts his all into it, causing destruction and shockwaves that his powerful aliens must deliver.
For the Ultimate Aliens, they were the superb factor of the show. Problem is that there are just few ultimate aliens. They also eradicated that silly timer because most of the plot arcs brought powerful and demanding villains such as Eon, Aggregor, Ultimate Kevin, and many others. For me I believe ultimate alien is a great way of at least keeping the consistency of a great franchise.
