For the cons:
1&2: They are interpretations of the character that make sense in the medium that it was used in. The idea that something has to be completely like it was in comics when its translated in the movie doesn't make sense to me.
3. Because its common for movies to have love interests. Why not introduce other women? Because most of them are superficial, like Vicky Vale (ie she doesn't know about his secret, classically) and Catwomen and Talia would be far too prominent in the movies. He didn't want to take that direction.
4: Its necessary IMO. Everyone knows this interpertation of Batman wouldn't work with the JLA, but to neither would a gritty Batman from his more Noir like stories. The character is somewhat adjusted when he's in the JLA.
Agreed on the pros though.