i'm personally not worried about the conformation times, there are many ways to fix that problem, such as using coinbase, or some other trusted third party.
my concern is the limit. what are we going to do when 98% of the currency is mined, and a vast majority of it is held by a few people, as it is now?
my personal suggestion, would be to make the number of bitcoins unlimited, but always produce the same amount every year. that makes bitcoin predictable, and keeps it valuable.