Thoughts on increasing MTUs on the internet

Dear NANOGers, It irks me that today, the effective MTU of the internet is 1500 bytes, while more and more equipment can handle bigger packets. What do you guys think about a mechanism that allows hosts and routers on a subnet to automatically discover the MTU they can use towards other systems on the same subnet, so that: 1. It's no longer necessary to limit the subnet MTU to that of the least capable system 2. It's no longer necessary to manage 1500 byte+ MTUs manually Any additional issues that such a mechanism would have to address?