At last, we learned what really happened to Coulson in Tahiti. Apparently, Tahiti is less magical place and more advanced scientific robot reprogramming your brain. Visit Tahiti at your own risk.
SHIELD's actions in resurrecting Coulson raises an important questions of ethics and power.
The ethical questions, when is someone dead or when should someone be allowed to die/put out of their misery, are incredibly difficult to answer. Jobs exist whose sole purpose is to debate and discuss these types of ethical medical quandaries. The Terri Schiavo case from 2005 and the current situation of Jahi McMath are high profile, real world cases that raise the same questions, but plenty of other lesser known cases exist too.
If you're looking for answers here, you've come to the wrong place. I have 300 words, and little life experience to draw upon to answer such important and complex questions properly. But, I firmly believe that these are important questions to think deeply about.
The issue of power, however, is much more clear. SHIELD is a vast organization with seemingly no checks or balances. Yes, an authority structure exists, but the organization seems to act with unlimited power. Personally (and really, why are you reading this blog if not for my personal opinion), I blanched at how SHIELD dealt with Coulson. Even one of his doctors balked at his post-death medical treatment, yet this didn't stop SHIELD. Director Fury's command required unquestioning obedience; ethical questions be damned.
In the face of such unbridled power, I think we can draw a conclusion about how much power we all our government. I'd spell it out, but why waste time. You're on a conservative website. What do you think that conclusion is?