BA 12 is more like $650-$675 in a 9.8, and NM 98 is in the $400-$450 range. NM 98 is a true first appearance of a currently popular character, BA 12 is simply the first appearance of a cartoon character in a comic book. People over estimate the importance of BA 12 in the hobby, and as more and more 9.8 copies hit the census, the lower the price seems to go. NM 98 has tons of 9.8's on the census and still seems to rise over time, although slowly.
-J.
I agree with you re: prices will fall as more 9.8s hit the census, just like with every other book, but your comment re: importance of NM 98 vs. BA 12 is wrong. Deadpool is an good character, but does not have the widespread appeal of Harley across both male and, more importantly, female collectors. That is the most important factor for comics as a whole going forward, IMHO. As more female readers and collectors enter the hobby characters like Harley and books like Saga will become more popular. I have been seeing it at shows the past three years especially after the DC New 52 relaunch - male and female collectors buy Harley books equally, but it almost entirely male collectors with Deadpool.
FWIW, the way Marvel is treating Deadpool right now with crappy mini after crappy mini I can see the franchise going the way of Punisher in the late 80s to mid 90s - overexposure can kill a good thing as well. DC is going to run the same risk with Harley if they overdo it.........