Just because fans didn't receive the original monsters from those newer films very well, doesn't mean that an original monster won't do well with fans or the general public with this one. At some point, all the monsters were fresh new faces. Seriously, we can't just say "Oh, we (the fans) didn't invest too much in this particular monster so that means the general public didn't like them either".
But David Goyer is the writer, knowing him with Batman and Blade then he is likely going to pick a classic villain for the film. Most likely pick someone that is iconic or a monster is recognizable like King Ghidorah or Hedorah. Having a new monster will be asking who they are, you don't see people making new original villains for Spider-Man in a film.
Bram Stoker's Dracula
because what movie nowadays doesn't get a trilogy?
(1992), Independence Day
(1997), Deep Blue Sea (1999), Daredevil
(2003), Van Helsing
(2004), 10,000 BC
(2008), The Last Airbender
(2010) and many other popular movies never got a trilogy. It's too early to tell if we are going to get sequels, the movie can be a hit (Which is likely) or a flop. GINO did well at the box office due to the marketing.