Okay, I have a few comments on this.
1) The advantage of the first one, I know what you mean, but you said it like it will make you more vulnerable. It makes you less vulnerable for you aren't 'stuck' in mid air anymore.
2) The disadvantage. It is quite simple if you think about it. You can change directions at high speed, meaning that when you are flying into another direction your speed can be a problem. What if the opponent decided to create a wall in that direction? You then should use it again to get out of the way of that wall, meaning you have one jutsu less to use in your move. This can be a disadvantage.
3) Like you said, you cannot 'defend' yourself from this jutsu, however you can stop the opponent from flying and attack them at once. This is an offensive-defence for you will use something offensive to them to defend yourself from a potential attack from the opponent. Or more simply said, you could create a wall somewhere behind them where they will fly against, causing them damage due to their speed.
4) The second jutsu might not really have a disadvantage, though it being short ranged would be the most obvious one.
5) Going underground whilst the opponent can see you is never a good idea for they will know you are underground and thus can launch an attack on you, for this they don't really have to know where you exactly are underground, they only have to be clever

You could rather, like cookie monster said, move out of range or overpower the technique, this is always save.
Any questions up until now? (I won't bite lol)
@ both of you, as you have seen from my reply, I like long answers, so I won't complain if you both write some more

This isn't necessary though.
@ cookie monster, I don't have much to say on your reply lol