You can take this with a grain of salt, but my friends at Bandai US tell me the top 4 Heisei series in popularity within the US are in order:

Build
OOOs
Gaim
Double

Also, the Kamen Rider initiative over the past year was considered a huge success and there's a lot of cool stuff coming as a result. I'm pretty stoked for this Anniversary celebration. 50 is such a milestone for any franchise. It makes me think about all my favorite shows from the 80s and 90s that I still celebrate despite not having any form of new media and just an occasional new collector toy here and there.

Cool, Build would be my second pick.

You know what they should do: RELEASE MORE THAN THE FIRST TWO EPISODES OF EACH KAMEN RIDER SERIES!!!!

Except that every series that has more than two episodes doesn't get official subtitles for them.

Those four are pretty unsurprising -- I see them talked about a LOT within many corners of the fandom, and in general there's a trend towards Heisei phase 2. I wouldn't be surprised if Den-O and Kuuga weren't far behind, mind.

I'll admit to being a bit surprised that Gaim isn't higher but perhaps the love for that is just louder than it is predominant.

I am definitely looking forward to this! Maybe they'll announce official Blu-Ray and DVD releases of Kamen Rider, maybe the next series' trademark will be revealed as well, since it's usually around April we get word of it. And if they premiere any Rider movies I have interest in, I'll try to see it when it comes out.

The trademark may be filed, but Toei won't officially announce it until June or July.

Okay, my bad. Thanks for clearing that up, I don't know the exact details of these things, so I really appreciate your information.

New fan here - Figuarts reveals? (fingers crossed)

Would love to see Rampage Vulcan and All Zero

Think there was an Ikazuchi showed earlier but no release date?

Wrong event to ask for that, friend. BUT, Tamashii Nations will be holding a 50th anniversary Kamen Rider event in TM Tokyo on April 2nd. They'll be revealing a new item there.