This is my main concern, but are there any other design flaws with Bitcoin?
TL;DR: Change of computer calculation power doesn't affect the price at all.
Market Price of anything determined by supply and demand, bitcoin is not exception the only difference is that the supply side is constant, 50 BTC per ten minutes at the moment. Regardless of how much computer power used to generate bitcoins the rate of produced bitcoins will not change because Bitcoin network difficulty will adjust to make it harder or easier to find new bitcoins depending on total network computer power, bitcoin price change purely because of change of demand.
Also there is a controversy about certain aspects of Bitcoin, but there is no designing flaws that I know of.
7,200 BTC a day is mined whether there is 200 rigs hashing away or 20,000.
The rate can climb slightly but every 2,016 blocks the rate of issuance gets recalibrated back to being once every 10 minutes (at 50 BTC per block then is 7,200 BTC per day).
The block reward subsidy will be changing in a couple months, to 25 BTC per day so the daily issuance is going to drop suddenly by half, for the next four years after.