You know CAP theorem.
Says that a PARTITIONED system cannot be simultaneously CONSISTENT and AVAILABLE.
So bitcoin network has to enforce periodically some rule for nodes to become CONSISTENT like agreeing on a common time.
Else eventually the system will always split in two highly AVAILABLE but not CONSISTENT parts (block chain fork)
Bitcoin is just fine but talking about ways to improve it by relaxing some requirements in favor of a simpler behavior (such as using some external time references widely available over the internet) i think always helps. For example there is an ongoing discussion on increasing transactions volume
I think many would disagree with the premise of the statement that using a central server is an improvement, whether it be for time or anything else. Likewise, most enjoy discussing well thought-out proposals that could be used.
Centralization opens up more attack vectors and is the antithesis of the protocol design, so I think you'll see a lot of resistance to anything that centralizes things and many people wouldn't switch to a fork that includes centralization by design.
:-)