This would be helpful to bring to the reddit page. That said, two things to discuss: one is about the 70bil coins. I don't think at all that the total number of coins is a big deal. It's not the total but the stability that investors looks for. Stocks of companies trade and sell at all values regardless of price, so I don't see how that would affect anything capping the coins lower, besides maybe an initial shock jump in value.

Second, I see the 6% jump down to 1.5% to be quite large, as well as the 20% to 12%, at least if there is going to be a 4% drop in the sequential years that follow. What about a exponential curve starting from 20%, and maybe decreasing more often? For instance,  just as a mockup, here is 20/exp(0.2*Time):

1    16.37462
2    13.4064
3    10.97623
4    8.986579
5    7.357589
6    6.023884
7    4.931939
8    4.03793
9    3.305978
10    2.706706
11    2.216063
12    1.814359
13    1.485472

As you can see, after 13 time periods, the inflation rate is at the target 1.5%, as previously suggested. Or, another thought is to change the rate when the total coins reaches a certain amount. For instance, at 20bil coins, change to 16.4%, at 27bil change to 13.4%, etc until at 70bil coins change to 1.5%. Just an idea.