The wealth accumulation is the most worrying part, for instance there's a transaction for 140k already, and add 8 zeros to that if the adoption trend goes viral. Then there are the mining pools, which effectively act as banks, only that you put your trust in some guy sitting on some couch. All kinds of strange things are happening in the pools, from roundings, opaque pool operation (You simply have to trust that the pool allocates you the right amount for your work, the pool operators even say this mockingly, ex. "But I'm goofing around for few week and I'm amazed with bitcoin idea, so I don't plan to steal anybody right now
:-)."
http://www.bitcoin.org/smf/index.php?topic=1976.0), etc.. A currency system based on trust? Meh, I don't see it happening (But then there are really bad actors on youtube that get really famous, sometimes even because that they're so bad, so you never know).
Let's not forget the large botnets, they can easily be focused on directly stealing the bitcoins, with no sort of security system your bank might have.
They also speak a-lot about the limit on inflation, since only 21 million can be generated (It's unlikely they all will get generated as the difficulty increases exponentially, good luck hitting a hash smaller than 0x000000000
... 0000100000000, or whatever the difficulty), but this means that those with let's say 5 million each, they will effectively be able to control the bitcoins' value.
And ofcourse the points you mention, such as what if some professional people decide to put in serious effort and money into finding a more equal system, and it ends up replacing bitcoins where many people have invested so much.