Lets see if I have this part right. You believe in what he did? You also believe we need more whistleblowers like him? You think we should make it easier for whistleblowers?
So back to may question. If the government does illegal activity but it stops a terrorist act are you OK with that? Do we need them to do more of that and make it easier for them?
I think Manning was a bit careless with what he leaked and crosssed the line. That being said, people are complicated- Manning did both good and bad with his leaks, and I would like other whistleblowers to continue leaking "good" info and not get punished for it. Manning on the other hand, seems like he was punished for the bad but never credited for the good he has done for this country, until now.
To answer your 2nd question, no, the ends don't justify the means. If you have to commit illegal acts while trampling on the rights granted to citizens in the Constituion to potentially stop terrorists, then the terrosits have already won by causing citizens to lose part of their freeedom. Whistleblowing -though usually considered illegal by those being exposed- if done right, is essentially giving Americans their freedom that they were constitutionally promised. And I may be a bit extreme, but I do believe in collateral damage here. If the only way to protect Americans freedom is by putting some people in risky positions, so be it. We Americans have never worried about fighting or risking our lives to protect our freedom.