As a miner of ETH (not currently due to XMR profitability) this is a bit disturbing, and I don't really even agree with the premise or impact of what they are proposing here. But, I also am holding a decent # of ETH coins in advance of the move to POS, so I am somewhat leveraged either way. But... speaking of the move to POS... isn't that going to happen in about a month anyway? I heard in several places they were expecting that to happen around Feb, which would render this whole block reward chopping almost useless if true, right? So, they want to kill the last month of ETH mining? Not sure but maybe that POS move isn't happening that early after all.
According to the links posted by OP, the reward reduction would happen simultaneously or thereabouts with a change to the block time so that the ice age (difficulty bomb) won't force the change to POS as quick, as they are apparently not ready for POS.
I have a couple of problems with the reduction in reward.
Firstly, they are justifying the reduction as a result of the drop in ETH value which has resulted in difficulty paying developers. Well, from what I can tell they have about twice as many developers are they should have, in that all of the software is duplicated in two programming languages. You have Eth and Geth, then Mist and GUI wallet, etc., IMHO they would have better quality software if they focused efforts on 1 version of each tool, and they would also be faster to achieve a switch to POS.
Secondly, is it acceptable for the EF to actually attempt to manipulate the value of the currency? It seems somewhat of a conflict of interest in that their contribution to the value of the currency is supposed to be the network and tools, as opposed to speculative endeavors that favor a portion of coin holders, that being themselves. Shouldn't the value of the coin be determined by market forces which respond to demand (or lack thereof) created by the perceived value and utility of the coin/network?
Lastly, Vitalik Buterin stated he didn't believe in democracy when "tramples the rights of the minority" (my paraphrase) so if there is a vote on this I would hope that more than a simple majority would be needed to pass.
In the case it does pass, there will be a number of specific blocks/dates where the value will change, making this a dream for speculators.
Fundamentally I don't beleive miners would be dumping this or any other coin if the value was increasing, and if miners hold a minority of the coins, doesn't that suggest there is not enough "utility demand" to sustain the value?