The technological shortfalls in RFID

Hi everyone,
I am doing research on the technological shortfalls in RFID implementations/systems/technology, but I am short on time! Do you have any suggestions or identified shortfalls?

So far I have
-> Middleware to (corporate) networks typically TCP/IP
-> Optimization of readers
-> interference between co-located readers
-> low cost short range reader
-> mostly all digital readers

any other suggestions or books I may consult?

Thanks
Slayer

cost is the big one, not alot you can do about it though

There is and international industry association called "RFID tribe".
They have a web site http://www.rfidtribe.org
and a Yahoo Group http://finance.groups.yahoo.com/group/rfidtribe, which message archives are very useful.