What are Ethereum’s faults/vulnerabilities?

I own it. I see the probable value. But there are plenty of stories and ideas about it's vulnerabilities. Now, if I'm wrong, I'm wrong and would appreciate some direction to the correct information, but:

• Is there a contingency if something happens to Vitalik, incapacitated, kidnapped, death, ect. Who or what system takes over going forward? Not wishing anything on the gentleman, but you never know. How much does his presence impact the value and future of the project?

• it enables decentralized functions but is it decentralized itself? is it dependent on specific servers or systems to continue operations?

• are there systems or teams in place that seek out and identify short comings on multiple levels?

• what are your criticisms of the project?

again, I'm just looking for clarification.