I wasn't a marketing major so I am throwing this out there for comment ... My initial reaction to hearing about the switch to 100.3 was "cool, now I won't have to switch the channel as often when traveling." But on further thought, I can "nearly" always find a game no matter where I am within the state. So, is the true significance to the switch that a larger station will equal larger advertising revenue? Won't bigger companies want to put more money into advertising during games now that they know there is a predominant station in central Iowa? Or perhaps advertising is just advertising and it won't make a significant difference?
There will be a bigger advertising benefit from having the FM station over AM, in my personal opinion, because of the target audience. There are a lot of benefits with going FM such as less interferance from weather, better penetration into office buildings, younger target audience, ease of switching stations, etc. My personal opinion is that you are likely to not only see higher quality advertising, but a few completely different advertisors as well.