Saban made the show as something new to fill a previously un-filled gap in children's TV back in the 90's, all Disney sees PR as is a cashcow, funds from which have been syphoned off to crap like HSM Sequals rather than spending the money on making a better show without blowing most of the budget on over-the-top explosives "effects".
The only thing Agito and Kiva have in common are some of their alternate-form motifs. That's about it. Agito's got great, well-rounded characters that actually contribute in the major picture and Kiva... Kiva has, uhh... uhhhhhhhhhhh.............. >_> <_< ...Kivat?