I was bored so I decided to calculate the most requested Strive characters that aren't currently in the game from the polls. I used the data from ALL the polls from seasons 1, 2, and 3 to calculate this. Here's what I got:

1 Dizzy

2 Jam

3 Robo Ky

4 Guest Character

5 Venom

6 Order Sol

7 Raven

8 Kum Haehyun

9 Zappa and Answer (Tied)

10 Gabriel

I was surprised at how high Guest Character ended up being, even higher than Venom. I put Jam above Robo Ky because Jam has existed consistently in the polls for ALL seasons. Robo Ky just gained popularity in recent times. Order Sol pops up a lot randomly throughout all the seasons so he ended up being higher than expected. Raven actually showed up in the top 10 of almost every region in Season 3, which is pretty cool. The characters below that (Kum, Zappa, Answer, Gabriel) have shown up at least ONCE in a single region.

I'm very interested to see what characters they're gonna add in Season 4!