Theme is an important difference, but to me what it comes down to is supply and demand. Seems like Stern rushed through this title to get to Spike games that have the bigger display. This game could have been epic if it had the larger display.
People complained about early code for years (Who brought the dog?) When they finally updated the code they didn't capitalize on it by running more games. Star Trek had multiple runs.
Another thing I'll throw out there is layout. To me Spider-man, Star Trek and Star Trek next generation are virtually the same layout. Ghostbusters is different for somebody who has one of those other games already.