I've updated the title as a BIP. The point wasn't to blame Satoshi, who got so much right.
The reason the 4 year cycle does create price spikes and big falls: when the inflation halves suddenly, prices have rather dramatic upwards pressure because of the supply curve shifting left. Then, what follows is FOMO, culminating in a peak and fall. AKA, boom/bust cycle.
If the inflation were per-block and gradual, we'd at least remove this sudden shock problem.
Adoption would be more steady and serious about using bitcoin as a stable increasingly valuable money. Such adoption could happen over the entire 4 year term, not just during the short upward cycle, like now, with everyone waiting for the next rush. It's not healthy for any realistic currency.
Bitcoin is not unstable due to halving actually halving process to limit the overall supply only. Halving should cause increase in price only not the downward turn. It is unstable because community is governed by the "HODL" principle. Very basic requirement of currency is that it should circulate and widely accepted, easy to transact and not counterfeit.
Unfortunately in current scenario , community instead of creating business (that will involve transaction of currency) believes in locking it.
PS: Stop blaming Satoshi ,he is not asking to dump the coin or spike the price.