There's no reason to issue more bitcoin. The forces of supply and demand will keep the value stable, regardless of the exact number of bitcoins outstanding. Issuing more bitcoin would only serve to invite fears that it would be issued in shady ways, or that such issuances might become routine and inflation would take place. This would only further undermine the currency's perceived staying power.
Unfortunately humans are famously loss averse[1] which leads to downwardly sticky nominal prices[2] in practice. In the face of deflation a lot of people just stop buying and selling and hope that prices go back up, or hold out for a nominal offer as big as what they think they "should" get even if the real value is the same.
If your bitcoin economy is full of nerds who really understand the subjective value of money than that's fine. But if you were to start having lots of normal people using Bitcoin and denominating prices and contracts in Bbitcoin than deflation would be a huge problem. As long as most of the surrounding economy isn't using Bitcoin it still wouldn't have the positive feedback loops that caused the Great Depression under the gold standard, though.
Why do you think "forces of supply and demand will keep the value stable"? Bitcoin is much more susceptible to huge valuation fluctuations than fiat currency, where central bank can step in to shift demand/supply.
