The bitcoin network spends 25 BTC every 10 minutes on security, that's $33k per day. How much does it cost to elect 17 witnesses? ...Once one person does that, it's goodbye chain.
This.
There is no doubt that Bitcoin has its weaknesses in both decentralization and security (those are not always the same). But anyone claiming that BitShares, as it stands today, has security anywhere near that of Bitcoin is in need of a serious reality check. If you want to attack the Bitcoin network directly (disable it), you need to attack ~6000 full nodes and disable a good chunk of the mining power so that block processing is effectively disabled. With pool-miners essentially able to switch pools at a whim, this must be an extremely difficult operation. If it was feasible (with Bitcoin's 3-4 billion USD market cap) it would have been done already. Let's not arrogantly dismiss Bitcoin's
proven security.
As far as I can tell, one of the real dangers to Bitcoin right now is someone controlling a majority of the core devs and driving opinion that way (opinion influences nodes and miners). The recent block size debate has taught us that is still a weakness of Bitcoin. Taking control of mining power is extremely expensive, and can today only be done by huge actors that are good at staying hidden for an extended period of time.
BitShares may be be doing things more efficiently than Bitcoin, but I'm struggling to see how a big actor will have any problem whatsoever taking down 17 witnesses running on 300$ a month. Now I'm not a hacker or security expert, but I've seen how something so small as the newly set up Norwegian Pirate Party DNS server (combatting Pirate Bay censorship) may quickly find itself under heavy DDOS fire. Why would something like this not pose a danger to the BitShares network, with our portfolio of powerful enemies?
I'm thinking that if there is a possible attack vector into BitShares, it will be used. Distributing witness control over several 100 will make it more robust. We need to be proactive with BitShares security, better too much than too little. If the BitShares network is only once attacked and driven to a halt, the crypto community will nod their heads and go "Mhm, that's what we thought. Game over."