I think it's just mostly a preference on looks than anything else. I do agree about the shot direction advantage that the F2 offers, but the F7 allows for the ball to glide off the face when it's not hit quite centred, so you may get a boundary instead of a single at times. You could argue and argue all about it, but in the end, a bat that you are confident in is the most important. If you like a particular camber on the face of your bat, then go for it!
On the technical side, F7 offers a lighter bat, as there's less volume off centre but the same amount down the centre of the bat. Would recommend anyone who is a touch player or uses a 2.7 and below to go for a rounded face. For me, personally, I don't care so much anymore, but I think I'm more inclined to go with 4.5. I just try to hit the ball and look for runs. If it goes into a gap, it's a bonus to me! I would love to be able to say I always think about where I place the ball, but it's definitely not the case!
Initially, I didn't like the twist I got on flat faced bats, but I think that was most prominent when the edges were thin. Now I don't mind it so much, not sure if it's because I'm missing more balls or I'm middling more!