Since the root cause of what you are trying to address is the reward having, I'd suggest considering an adjustment to the having schedule.  Instead of their being a large supply shock every four years, perhaps the reward could drop every 52,500 blocks (yearly), or even at each difficulty adjustment, in such a way that the inflation curve is smoothed out.  The exponential decay rate would be preserved, so overall economic philosophy would be preserved.

I'm guessing hesitance to this approach would lie in a reluctance to tinker with Bitcoin's 'economic contract', and slippery slope concerns about might be the next change (21M?).  However, I think it could actually increase confidence in the system if the community is able to demonstrate a good process for making such decisions, and show that we can separate the meaningful underlying principles, such as the coin limit and overall inflation rate, from what is more akin to an implementation detail, as I consider the large-step reward reduction to be.

I'm not too worried about the impact of the having as is, but adjusting the economic parameter would be a safer and simpler way to address the concerns than to tinker with the difficulty targeting mechanism, which is at the heart of Bitcoin's security

On Wed, Mar 2, 2016 at 6:56 AM, Luke Dashjr via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:
We are coming up on the subsidy halving this July, and there have been some
concerns raised that a non-trivial number of miners could potentially drop off
the network. This would result in a significantly longer block interval, which
also means a higher per-block transaction volume, which could cause the block
size limit to legitimately be hit much sooner than expected. Furthermore, due
to difficulty adjustment being measured exclusively in blocks, the time until
it adjusts to compensate would be prolonged.

For example, if 50% of miners dropped off the network, blocks would be every
20 minutes on average and contain double the transactions they presently do.
Even double would be approximately 850-900k, which potentially bumps up
against the hard limit when empty blocks are taken into consideration. This
situation would continue for a full month if no changes are made. If more
miners drop off the network, most of this becomes linearly worse, but due to
hitting the block size limit, the backlog would grow indefinitely until the
adjustment occurs.

To alleviate this risk, it seems reasonable to propose a hardfork to the
difficulty adjustment algorithm so it can adapt quicker to such a significant
drop in mining rate. BtcDrak tells me he has well-tested code for this in his
altcoin, which has seen some roller-coaster hashrates, so it may even be
possible to have such a proposal ready in time to be deployed alongside SegWit
to take effect in time for the upcoming subsidy halving. If this slips, I
think it may be reasonable to push for at least code-readiness before July,
and possibly roll it into any other hardfork proposed before or around that
time.

I am unaware of any reason this would be controversial, so if anyone has a
problem with such a change, please speak up sooner rather than later. Other
ideas or concerns are of course welcome as well.

Thanks,

Luke
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