1) It is NOT anonymous at all. In fact it's a government's dream come true. *All transactions* are irrefutably logged and available to everyone.
All you have to do is associate addresses with individuals. Which with government alphabet soup powers is not too difficult, not to mention hackers, trojans, key loggers, and real world eves-dropping/monitoring.
Also, imagine a court subpoena of your wallet or outright seizure. Every address you have ever used is in there and every expenditure and receipt is in the public block chain.
This is probably of little concern to most users but see #2 below.
2) The utter ridiculous hassle of having to deal with multitudes of addresses to get any measure of privacy or know who sent you bitcoins.
No Mom, that's your address this time, really, it just changes every time you use it. No it is him. The money Uncle Ted sent you was sent to this address see, that's how you know it's from him. No, that was the address from before, it's different now. No, when Chris sends you money it's this address. No, you're suppose to use this address for now with Aunt Sally. No, it still in the same wallet. No, they are all different ... ! ... look ... how about I just get you a prepaid VISA card?
3) A very very tiny handful of people own a significant percentage of the entire money supply.
When the difficulty was extremely low the mining pay out should have been at a tiny fraction of a bitcoin instead of 50, and then increased as the difficulty increased, up to a limit of say 100 at a difficulty of 2 million, then slowly decrease due to time as slated to do. This would have provided a chance for bitcoin to be dispersed into far more hands.
It still would have given bitcoins to the creators and first users just not at a mega-royal amounts.
As it is, we have a few people sitting on gargantuan hoards.
In comparison, it would be like a handful of people having 3-4 trillion U.S. dollars sitting around. Yes, over the years as more dollars were created the dollars would be worth less and a smaller percent of the total supply. The exact opposite is true with Bitcoin.
4) The complexity of the entire system is easily handled by tech people but the iPhone crowds can't and won't try to figure it out and if they do try they will get aggravated by the complexity and fleeced because they don't know how to protect their wallet or privacy. In other words, it's the Linux of the currency world. BTW I have a strong suspicion that Torvalds is Satoshi!
(j/k)
5) The slowness of the transactions. Waiting ten minutes or more to be sure the payment is valid is a huge draw back.
Of course you can use places like MyBitCoin for immediate payments, but wasn't one of the main selling points of Bitcoin that no middleman had to be trusted?
Well not if you want timely transactions. So it's really no longer a selling point. Especially in the wake of MyBitcoin.
6) The lack of ability to do true micro payments (less than USD 1 cent). Due to the concern of network bog down with millions of micro payments, they enforce transaction fees that make micro payments worthless. Solution? Yep, back to a middleman. Please visit my site: BitcoinMiddleman.com(j/k I just made that site up.)
7) The best medium of exchange is stable, neither inflating nor deflating. The response is that bitcoins are divisible to eight decimals places.
So what. That doesn't change the fact that it's deflating. Yes, holding onto a deflating currency is great, especially for those holding huge amounts, but what does constant deflation do to the Bitcoin economy at large? Has anyone studied any economy or currency that had *perpetual* deflation?
8 ) Since bitcoin is like cash, it's a thief's dream come true, because once you send the bitcoins, they're gone. The scammers and con artists will ceaselessly zerg the Internet from the convenience of their terminals in far away lands, in their never ending quest to steal anything they can.