Are there any negatives to this fix?
I suggest reading this thread.
Seriously. such an embarrassment. So much grunting and flinging of poo and people don't bother to read messages of actual substance.
Here's my summary of the substance.
The "negative" is that old, defective implementations will no longer work. Users of these defective implementations will have to upgrade, or if that is not possible, they will have to export their private keys and switch to newer software.
Some of us believe that this is not a "negative", rather that it is a "positive". The fix is not just a convenience fix, it is a security fix, because the continued existence of the bug admits for denial of service attacks. It also enables malevolent cancellation of transactions that depend on unconfirmed transactions.