The decision to undergo a rhinoplasty is a very personal decision. Given the fact you have had 2 previous operations I am sure you are not taking this decision lightly. I would recommend you discuss your specific concerns with your surgeon and she can tell you if those can be addressed to your expectations. You will want to make sure there is a clear understanding between you and your surgeon on your goals to be achieved with surgery. While your surgeon can advise on what results are possible, only you can decide if you are ready to undergo a procedure.
Do it again? Perhaps. Depends on what you want to have changed.
In general, for a revision operation, the bigger the changes that you are seeking, the more likely that a revision, in expert hands, is a reasonable idea. Since we can't make 100% of the changes we want to make, if you're only looking for a tiny tweak, it's not such good idea, since if the surgeon misses the goal by a tiny amount, then you might not get any improvement at all. If the goal is to make bigger changes, then it's more likely that you'll like the outcome, even when the surgeon misses the goal by a little. See the "Web reference" link, just below my post here. I made a modification to one of your images, and an animation of the modification, to show some proposed changes. Perhaps you could comment on whether I'm on the right track. I elevated the tip of your nose a bit, brought the tip back closer to your face, lowered the prominence just above the tip. I also added some strength to your chin, because it's a very safe procedure, and it's a good way to draw attention away from the nose and make the nose look smaller. It would also be reasonable to elevate the tip of your nose even more, lower the bridge even more, and add more strength to your chin, depending on your preferences. You should understand that the changes I demonstrated in the morph require advanced techniques, techniques that most plastic surgeons cannot handle. Be sure to read the section in the "Web reference" link on how to stay out of trouble while searching for a rhinoplasty surgeon.
Your nose is also a good example of why computer imaging is mandatory in rhinoplasty. You need to know exactly what the surgeon is planning to accomplish -- what features he thinks he can change, and by how much he thinks he can change them -- so you know whether it's enough to be meaningful to you, and whether he understands your wishes enough to address all of your priorities. Then, he must show you before and after photos to prove that he can actually accomplish what he draws on the computer.
It is not very common for patients to have a third revision procedure. Without details about why you need a revision, it is difficult to provide a good answer. If it has been less than a year after your second rhinoplasty, your “new nose” needs time to settle in and for swelling to reduce completely. Before thinking about a revision procedure, make sure you have given your nose enough time to complete heal. Generally revision procedures are more complicated than primary rhinoplasty as the surgeon will have less to work with. I recommend visiting a board certified facial plastic surgeon for a detailed consultation. The structural integrity maybe a concern especially if you had two rhinoplasty procedures already.