I will say I think my love for Agito grows over thyme (ayyy)
I do feel there's no real requirement for it's connections to Kuuga, all the mentions of Kuuga could of been waved at some vague event or prophecy or something. However, it's connections to Kuuga doesn't hinder it, other than it may give you tonal whiplash if you come straight from Kuuga. Agito kind of has those sorts of problems as we brought kamen rider back where they were working out what they wanted it to be. This is more like what heisei kamen rider would be than Kuuga was. If you've got someone who can wave away not knowing the brief mentions of Kuuga, you could even start them off here pretty well.
All the characters are very likeable, the story is good, and I loved the comedy in it.
I highly recommend Agito, it's a great story, it's great comedy. Please, watch Kamen Rider Agito.
List of Series
Lupinranger vs Patoranger