User blog comment:Vinny Tennyson/Omniverse/@comment-24215679-20140506224614

Why Ben is unlocking aliens more frequently in Omniverse and Ultimate Alien as opposed to the earlier series

They are obviously adding new aliens more frequently to keep interest and because contrary to his own belief Ben is slowly learning more about the Omnitrix, and how it works. In the original series he discovered the scanner after a while of using it, he discovered voice control in Alien Force, Ultimate forms in Ultimate alien, and that life lock mode and randomizer mode existed in the Omniverse. The new things he discovers about the omnitrix help him understand how it works and understanding how a machine works is a part of using its full potential(Unlocking more aliens). However, he would probably have a vaster understanding of the Omnitrix and have more aliens to if Azmuth didnt keep changing the models.

Oh yeah, and notice Ben unlocked aliens at a slower rate in the original series when he was less mature and was a lot more brash about him being a hero and not needing Gwen and Grandpa's help. He started unlocking aliends more frequently in Ultimate alien and Omniverse when he became more mature about the fact that he was a hero and he had a job to do, and he started to accept help from others in the later series shown by his teamwor with Gwen, Kevin, and Rook.

Last, in the original series, Alien Force and part of Ulitmate Alien he referred to the Omnitrix as a weapon constantly. In the later part of Ultimate Alien and Omniverse, he began referring to it as a tool, showing maturity. Azmuth undoubtly monitors his use of the Omnitrix and maybe even what he says sometimes through the Omnitrix. Maybe Azmuth has somehow allowed aliens to be unlocked more frequently due to Ben's change of viewpoint from the Omnitrix as a weapon, to Azmuth's viewpoint that it is a tool.

Fin.