I think BFN needs a lot of massive changes to truly reach its maximum potential and bots is a pretty good start.
Other games have bots but in BFN it is more frustrating due to the lacking player base. I am going to start with a recommended way on fixing them. When the player base increases, the bots can be removed if so desired by Popcap.
1. Have bots only appear to even teams. 8v4 --> 8v8. When a player on the team with more actual players leaves it, a bot is removed. 8v8 --> 7v8 --> 7v7
2. Have bots have a delayed reaction to players that are to the left, right, or behind the bot. Right: 1.2 Sec Delay, Left: 1.2 Sec Delay, Behind: 2 Sec Delay.
3. Slightly decrease accuracy.
4. Fix any abilities being used during others and other bugs with them.
5. Give at least 75% Exp for vanquishing them or full Exp.
The ideas of bringing more players is a great idea, but advertising would have a much better time if a giant update was going to be added. It would be good due to it bringing a lot of attention to it.
1. Giant Update with balance patch, new characters, new map(s), new free customization in the Reward-o-Tron, and bug fixes would get current players hyped and bring back players who left.
2. Advertisement would get new players hyped and want to buy the game.
3. Community challenges and more feedback from devs would also give content creators and players things to go off of and generate hype as well.