In enter link description here, it is said that "We have already determined that our current algorithm is highly suboptimal on low volatility and non-exploitability, and at the very least we plan to switch the timestamps compares to be the parent and grandparent, so that miners only have the incentive to modify timestamps if they are mining two blocks in a row."
What does the 'switch' mean here? Besides, I think the homestead version is good enough. Where is the disadvantage?