In the process of doing something in the Waco market . What format would you say this small market is missing ?
There is a lot you haven't said that would probably make answering this question easier if you had. Specifically, is the station you're involved with AM or FM. Is it commercial or non-commercial. If AM, does it have an FM translator. The answer to these questions will help determine which format you should choose.
Also, what might help is a snapshot of the market, or at least the city of Waco and its demographics. While there are several private reports that can do this, I'll stick with the summary provided publicly by Wikipedia at the below link.
en.wikipedia.org
Looking at that summary, the three biggest ethnicities in that city are, in order of percentages, Hispanic (all races), Caucasian, and African-american.
So, using the Wikipedia data, plus one of the entertainment-based radio station listing sites, I would make the following recommendations:
If you have a commercial FM, I would go with either hot AC or AC. Both formats are listened to by females of all three of the largest ethnic/racial groups in the area and currently Waco does not have a hot AC or AC station serving the market. Between hot AC and AC, the former is skewed at younger audiences while the latter is skewed towards older females. (I didn't check the age demographics of Waco).
Because of its current demographic size, a regional Mexican format aimed at the Hispanic market might be worth a shot, though there is another station in the market doing that now. Beyond the competition that's already there, I'd not go for the regional Mexican format, given the recent executive orders signed by the new U.S. President concerning Hispanics.
If you have an AM with an FM translator, then I'd probably look at either a soft AC format or a 50s-70s oldies format aimed at older adults. I might also consider a white or black gospel music format.
If you have an AM without an FM translator, the white or black gospel music is probably a good fit. An all-agricultural or farm news/talk format would probably be even better, and if you wish to target the African-American audience specifically, carrying IHM's Black Information Network (BIN) probably wouldn't be a bad idea. You could also target a spanish news/talk format at the currently dominant Hispanic population.
If you have a non-commercial outlet, then targeting the very small Asian community might be an option; or you could do a community station format with a few programs provided by Pacifica. There are plenty of other options here as non-commercial outings do not need to turn a profit; they only need to earn enough money to pay for the cost of running them.
Good luck to you no matter what option you choose.