Ok so the extent to which peercoin still uses proof of work is the extent to which this will still be a problem. I really think sonny king should have put the phasing out of the proof of work on a hard timeline but hindsight and what not.

Ok so yea there are other problems with orphan blocks. So the bottleneck in how many transactions we can put in a block is not the block size being stored on peoples hard drives (as is the common misconception) it's how many transactions a miner can download. If we have regular orphan blocks, lets say 2/3 of all blocks a miner downloads are orphan blocks than the network can only reliably record 1/3 as many transactions as if the miner were downloading 0 orphan blocks since 2/3 of everything he downloaded is just garbage.

If you have TOO many orphan blocks than that can turn into a calamity. No miner can reasonably be expected to check all of the chains floating around so some totally honest miners would end up mining on a chain that isnt the longest because they simply hadnt checked all of the chains and hadnt located the one thats actually the longest. You could end up with a situation where honest nodes were doing the exact same thing that everyone fears dishonest nodes may do, saving up a secret chain and publishing it later. This would make confirmations unreliable, potentially even MANY confirmations could be unreliable, you could have 60 confirmations on 1 minute blocks and suddenly your client finds an even longer chain that that which was incubating hidden on some dank dark corner of the network.

Ok so about that post. Let me use an example. Imagine that we have A who is a single person and B who is a group of 10 people. Lets say they have the same hashing power. Lets say that it takes 10 seconds to propagate a block across the whole network. Lets say the block time is 20 seconds. Lets say that a is an attacker who wants to save up his own chain and publish it later inorder to double spend. A starts mining, in 20 seconds he produces his first block, 20 seconds from then he produces his second block ect... after 10 minutes he has produced 30 blocks. Now lets compare the group of 10. Group B are all honest. after 20 seconds the first block is created by B_1. B_1 publishes his block and after 10 seconds the rest of group b has the new block. They all start mining on it, after 20 seconds one of them finds the next block and he publishes it, after 10 seconds the rest of the group gets it and they start mining on it. ect... So we see that after 10 minutes group B has produced only 20 blocks. Even though group b has the exact same amount of hashing power as A they just cant compete. You can keep pushing this further. Imagine if it took 10 seconds to propagate a block across the network and the block time was 10 seconds. In this network if you had one dishonest miner with 1GH/s and 1 million honest actors with 0.75Gh/s each, his 1GH/s could over power all 1 million of them.