Whether it was poor planning or not, the ending sucked mountains of ass far greater than even Lucas can pull off. It was a movie with a direction to a point that didn't exist. Kinda like Matrix Reloaded, except there isn't a planned sequel.
The Nazis rose to power because Germany was economically fucked up by France. The only threat the Soviets posed was during 1941 (or so Hitler thought). I don't understand where you get your facts.
Venom was developed to be extremely believable and lifelike. The fact that he wasn't simply random guy #37 who gained super powers is what made him great. The fact that Eddie Brock was a fully fleshed character before the symbiote and the fact that the symbiote was fully fleshed before Venom...
Venom would suck because Eddie Brock hasn't been developed at all yet. Unless the movie ends like Matrix Reloaded, I don't see how they can pull off Venom decently (and if they do end it like Matrix Reloaded, I don't see how they can pull off the movie decently).