In order to survive, Core needs to change its PoW, or else Core miners wont be able to mine at all. I purpose the following, in order to prevent mining centralization, and prevent the possibility of such a governance coup in the future:
Rotating PoW change. Every 3 months (six difficult adjustments), Core will change (via hard fork) its PoW algorithm. There will be one month (4032 blocks) of overlap after each change, in which blocks created by both PoWs will be accepted. This will give enough time for upgrade after each PoW change. Every PoW change will reset the clock on any ASIC-ization effort. It will be madness to try to create a matching ASIC, when the PoW is changing every 4 months (1 month for the grace period).
This will completely eliminate the current situation in which two companies (BitmainTech and BitFury) can control over 90% of the hash-rate.
The mining playing field will be leveled again and the barrier of entry for mining will lowered. Everyone with money and access to low cost electricity will be able to mine. There will be no need to buy 16nm ASICs from BitFury at $13 per unit, when BitFury cost is $3 per ASIC (my estimation).
In order to avoid corruption in the selection of PoW algorithms, I also suggest that a committee of 5 individuals will be formed, with each individual serving a term of four algorithm changes (one year), with staggered cycles so the committee is not changed all at once. The preference will be to use complex algorithms, with multiple sub algorithms (e.g. X11 style), and the constants in each should be selected randomly from the block-chain data leading up to each rotation. As this is merely a suggestion for community consideration, I do not presume to define selection criteria for the committee members.
What about BotNets ?
Back in 2012 it was a real issues. These days there are entities with huge amount of GPUs. BotNets will be just another player. In my estimation they will be one of the smaller ones.