The difference in the inflation between Hive and BTC will be reduced over time:
Coins like BTC can afford to live with a limited supply because of their fee model but since Hive relies on a zero fee structure it will always need inflation to pay block producers.
Instead of reducing the issuance rate what we need to strive for is to create use-cases that require burning Hive to reduce the impact of inflation on the price. In another words we need to increase the proportion of inelastic demand. Although as a stake holder I wouldn't mind accelerating the reduction of the inflation rate at some point.
I agree - a certain part of the inflation is needed to pay the witnesses and this needs to be enough to make sure that witnesses do their job properly.