Bitcoin is just the first p2p cryptocurrency
Don't expect it to be flawlessly designed the first time, that seems highly unlikely
It doesn't need to be flawless today. Bitcoin can evolve when required.
It's actually far easier to hard fork than to get everyone to switch to a different coin entirely. With a hard fork, everyone's coins still exist on the forked chain. With a new chain, they have to liquidate their bitcoins and obtain newcoins.