On the one hand, I feel the transgender issue in her case is exploitative, riding upon the backs of the gay political movement. Perhaps many people follow her solely because she is transgender and happens to make the headlines. She is asking a lot in terms of medical care from the institution that she betrayed. However, in the end, it makes the military look good that they are providing her with recommended medical care.
On the other hand, perhaps her 35-year sentence does seem rather excessive. However, punishment in criminal cases is mainly for deterrent value. It is not Manning that society fears, but others that might do as she did in the future. That is the real explanation for a 35-year sentence. It is not that Manning poses a huge danger to society or that people want revenge against her (although some probably do, namely her superiors who were embarrassed by the leaks). It is not Manning, but the specter of future Mannings that the powers-that-be fear. Military justice is always about setting examples. Thus, a murderer may actually get a lighter sentence than Manning. It does not seem fair, but fairness ain't in it. Combat-readiness is the priority, not fairness.
In truth, jail sentences are a blunt instrument aimed at prevention of future crimes, both from the perpetrator and future perpetrators. Human justice often seems cruel and arbitrary. It is fear that keeps many people from doing things, and draconian sentences are intended to inspire that fear. I am sure that if Manning were released, society would not be in danger, but perhaps others would be tempted to do as she did, and in that scenario, how could the military keep any secrets? A larger question is, should the military keep quite so many secrets? Secrets sometimes exist for good reasons, but they also exist to cover up evil, corruption, negligence, and incompetence. What if the military had fewer secrets? Perhaps we could rid our military of evil, corruption, negligence, and incompetence. There are many advantages to openness.
I'd be in favor of reducing Manning's sentence, to make it comparable with similar crimes, if it can be demonstrated that the leaks resulting from her actions did not result in physical injury to others. That may be a rather high bar to reach. Perhaps the absence of evidence of harm would be sufficient.