Molina fell out of the limelight. He's done films, but "Spider-Man 2" really jumpstarted his career back into overdrive again.
That's actually better that he's not recognizable. Remember Batman Forever? No one thought "Hey that's the Riddler on screen." they thought "Hey that's Jim Carrey." The same thing is going to happen with Eric Foreman.
And here's my theory about Brock and Venom.
Brock is made small in this movie because he's just an ordinary guy who like Peter is pining for the chance to be top photographer at the Bugle. He's basically Spider-Man's id to his ego, the yin to his yang. I mean I think what Raimi is going for is symbolically they're the exact same people, it's just they've been handed different fates. Peter rejects the suit because it embodies everything he isn't, Eddie accepts it because he's let things like jealousy, hate, rage, anger, frustration, etc. get the best of him and the suit feeds off all of these things and that's why he grows bigger, stronger, faster, and meaner than Spider-Man.
I mean what is so wrong with having a small Brock anyways? It doesn't really fall out of the small Spider-Man history or canon. Brock started out as a normal thin guy till he started pumping iron and lifting weights and eventually became a bulky, muscular guy. Does that mean because of the pics we've seen of Topher right now he won't do the same?
Just give it time dude.