Firstly CS and TF2 both have air speed cap, so its not like people abuse the air strafe. To get great speed you need to remain on the surf pad and get very little air time, Its the same with normal strafe jump, in order to put in a good time have less air time. This is not about trying to abuse speed in the air instead of using a surf route.
We have to remember what surf is first, Surf was never about gaining times on a map it was mostly fun with some maps like surf simpson being a little challange on each stage. Later on people started adding in little switches to set times on maps but not many people really cared about those timer switches to much.
This game how ever is a whole hearted race game, and I think on that basis alone its a good enough reason to have control of every movement, instead of being restricted so to speak (handicap) in the air.
I will go into it further using the video you have linked me for surf4, its a good example of what im trying to point out actually. At 8 seconds into the video, the speed of the player has been transfered into height by surfing up to give him the velocity needed to make the gap. Theres a problem tho, Lets just say you need 460ups to make the gap (shown at 11 seconds into the video) but you only have 450ups as soon as you have transfered your speed into velocity and left the last surf pad before the gap. As soon as your in the air with those 450ups no longer than a second later your realize actually you need 460 to make this gap.
This is where the air speed strafe comes into it, I can compensate for any lose of speed and make up those 10Ups that matter to make the gap.
If Im surfing every pad knowing that I need "X" speed and "V" velocity, I will be able to tell if the gap is a fail or not as soon as I go into the air knowing full well what the "X" and "V" outcome equals without me being able to add in my own compensation.
So to reiterate, air speed is good for compensation.
Im a bit salty that some people would feel offended or think only surf players would come here, This whole defrag genre is based on people like my self who completely avoided playing any other game mode other than defrag.
If you go on the Reflex forums, you can see that a lot of people are Anal about adding in instagib because it would attract only insta gib players or gamers who only play on certain game modes. I know people that only 1v1, duel etc etc and Im sorry but I have to disagree with you, the very foundation of defrag was built with people exactly like that.
I host a reflex server, and I have gamers who come on my server all the time who have only ever played 1v1 matches (ego). I show some of them how to defrag instead of linking them to a website like a lot of other people do.
After a while I will have them thanking me for showing them defrag can be fun/challange and they would play it more often. I would not be so worried about only Surf players coming into the game and only surfing. This game has a great tutorial and more people would strafe than normal thanks to the tutorial.
I actually believe that, ive never seen a tutorial like this one, its much better than any youtube video minus the dialogue.