My bigger beef is that there are barely any standard award seats available. I checked and even when you could buy round trip for 177$ or even 142$ from DEN to BNA they did still not have seats available for a large date range using 20k miles.
I also checked DEN to LGA for a lot of days in June and nothing came up. WN has a lot more space available. For me the F9 program is close to useless with their tight controls on capacity.
Also with United I get 100% bonus on my miles, with Frontier its only 50% (I have highest status with UA and F9). So the 20k vs 25k is in reality 13.3k vs 12.5k BIS miles so on UA I do need to fly less to get the same award type.
I like F9 for various other reasons (good pricing, nice planes, usually friendly FA's, schedule works well for me, free booze, free TV) but for sure their mileage program is now far inferior to most others with their heavy capacity controls on available seats.
I have 70+k miles on it and have no real chance to use them.
Obviously there is the 40k level for Ascent and Summit that I can use but if I can buy a ticket for 200$ for the same flight the value of my miles is quite low.