It may just be a wild guess, yeah. But I would say the Orc/Griffin thing is different though. They are rather standard/typical HI with nothing fancy. Ryuken is on the other hand a very specific, almost one-of-a-kind, type of profile. That would be a bit redundent to have such similar profiles (only difference with the HRL loadout is basically exchanging mim-6 for mim-3 and HD) and a lost opportunity to make something nice and different with the Raiden.
For both the Senku and the Jizamurai, it looks like you should be relying on the 0 SWC Thunderbolts to close the range. With Mimetism, Jizamurai is a better gunfighter than the Domaru. Also, as MI, he is not threatened by hacking networks. This army feels like it will play differently than N4 JSA with more fragile troops.
Meh, it's mostly anecdotical and definitely not a defining feature. New Raiden and current Ryuken are identical/very similar in almost every single aspect, not different enough to justify to separate profiles. But we'll see, I'm not sure what they would do with the Ryuken then. "there, you have Raiden", then "guess what, Raiden is no more, similar Ryuken replace it", then "hey, surprise, Ryuken is no more, guess who's back? Yup, that's right, Raiden is back!".
There is also other differencies. Ryuken has mimetism -6 and 1 use only camo. Raiden is only mimetism -3, but has hidden deployment. They have slightly different usage imho.
And using both in a Vanilla Meme list would be really funny. You can can have a lot of deployment zone camo markers.
and what if you want to put 2 ARO pieces, but raiden is AVA 1 in vanilla? You can put a ryuken to complement. And probably the raiden will be not available in Oban, so at least ryuken HRL must stay there
These differences are already pointed out in my initial message. Slightly different, indeed. Which is the point. I'm not sure this slight difference justify having two separate Army entries. Raiden/Ryuken, even the name is almost the same! For slight differences, you can use the various loadouts of one entry (give it camo 1 use or not, HD or not, etc...). It would be more relevant to give each of them a proper identity and clear differences, diversity is always better. But anyway, we'll see how it is. Or more easily, CB could make the Raiden AVA 2 and get rid of the very similar Ryuken. There, problem solved.