How does a game that marked a boom in the modern fighting game genre can be considered a classic?? If it is a "boom" from the modern games, he is modern, not a classic.
If the "inky aftereffects" were "definitely" iconic, this move wouldn't be gone in SFV.
It is relevant to the argument because if the Focus Attack was so iconic and relevant, they wouldn't had removed it on the new game. If they removed it, it is because this move IS NOT so iconic. Did they ever remove the Hadoken? the Shoryuken? the Tatsumaki Sepuu Kyaku?
Nintendo will NEVER remove the FALCON PUNCH from Captain Falcon's moveset, because this move is VERY iconic, it is the most iconic move originated from Smash Bros., this is an example of an iconic move, not the Focus Attack which it was discarded by Capcom itself.
If we're going by that logic, Ken's having Shakunetsu Hadoken in one game isn't iconic either which is why Nintendo discarded this when making Ken.
Also, um, the inky effects ARE in SFV?
Anyway, to go back to the points you made in response to mine:
A. No, it's associated with Ken's VT, not Ken, unless you want to argue that Ryu is now an electric-user
B. No, that's giving a character moves from multiple games, fire roundhouse kicks are moves that don't exist, period
C. No, adding a meter to a character like Ken and Ryu would make the character gimmicky. You'd effectively be making a fundamentals character who gets kills using something similar to Limit.
D. Yes, let's give Ryu a move that takes away one of his best Neutral tools, represents something that feels like SFV specifically rather than something that feels like SF as a whole (The concept of Focus is much more "fighting" than the concept of VT)