What Adness should do is either pitch an animated (anime-esque) version of the original alongside an adaptation of a recent series.
My picks for adaptations would be:
Kuuga/Agito duology: This I haven't thought of and since I know nothing of it besides the first episode , I can't say anything for it. But with it's looks it can easily be TNG of the Masked Rider or perhaps a mythical themed one surrounding ancient history/ cyborg conflicts like in the first series. Could be well left alone in exception to minor updates/touch-ups/remasterings to the 10 year old footage. You might as well skip this if the budget perecived in doing this is outrageous for the revamp.
Blade/Kiva mashup: Use the concept of Ryuki for every rider for themselves , mesh it with the mystical and medieval concpet of Vampire and monster hunters , and have some of the riders being monsters fighting against IXA / The Hunters whilst combating X Villains ,thus creating dynamic series. This is basically VR Troopers but much better as new footage can be filmed to put the Riders into the same scenes .
Faiz/Den-O/Double trilogy arc: While Den-O seems highly unlikely for to be apart with Faiz or Double, you have to consider that adaptations do not have to keep the story or tone. Look at Dino Thunder , MMPR, In Space , Beetleborgs and RPM as examples. Besides that they have similar looks to them , possibly utilizing the futuristic looks of Faiz like a Time Force Kamen Rider whose technology evolves into Den-O much like the Thunderzords. Double's concpet can be of an experimental procedure that gives riders of Den-O a power on the cost of sharing the same body. You could even swap Den-O for Kabuto if needed.