all you've managed to do is swap the 'proof of work' system, which prevents gaming of the system, with a system that gives control to whoever can muster the largest resources in terms of IP addresses and virtual nodes.
Having scrapped the whole 'block' system - this 'arms race' would happen at a rapid rate, and even if there were a few competing botnets, control of the network would oscillate between them.
In short - your proposal sounds like a disaster, and suggests you've missed the point of the block system and proof-of-work.
Isn't that how it works anyway though? If an attacker manages to get 50% of the processing power of the network then he could potentially validate an invalid transaction (like creating bitcoins out of thin air).
If anything I would think that my system would be more secure, since an attacker would have to have 2/3 majority, not in terms of processing power but in terms of nodes. This security is inherit in the philosophy of bitcoins, and it depends on the philosophy that there will always be more genuine validators than attacker validators.