@Kaido I like JGL. But he's not a good Spike in my opinion. Spike in the anime is suave, mysterious, at times cold, and determined. I'm familiar with JGL's work - from his sitcom as a kid to his Nolan stuff. JGL is too 'nice guy' vibe to be a good Spike. He's too much theater boy vibe. (in my crappy opinion)
I know it's an anime, but also he's is too ugly to be Spike to be honest, LOL.
I can't think of a good Spike... John Cho was okay.
I saw Tom Holland in
Devil All the Time - a serious drama. He wouldn't be bad actually. His quippy fun nature as Peter Parker would translate well here as Spike. And boy he can play a serious and fearsome character - a good fit for Spike as well.
That movie also had Robert Pattison. Ohh that movie earned my respect for him as well. I can see him pulling off Spike. But he has blue eyes and blond hair and the face structure to go with it. Spike needs to be be more ethnic or italian something.