^You mean the battle where the soldiers calmly mow down the slow onslaught of thousands of zombies? Yeah, fast zombies won't add any excitement to that.
To me the problem is that fast zombies with a near-instantaneous infection cycle can't turn into a worldwide phenomenon.
Brooks explains very well how his slow-infection and slow-running zombies get worldwide - people get bitten and then get onto planes, or get carried across national borders by smugglers. You can't do that with a fast zombie that instantly turns.
A fast zombie plague originating in China completely destroys one local region and then gets nuked by the Chinese themselves. It doesn't go worldwide.
The whole cycle Brooks described - where the disease is just a rumor, then the Chinese suppress the news, then it slowly trickles out as infected people try to flee, then the West (other than Israel) doesn't take it seriously, then people falsely believe there's a cure, etc. etc. etc. - none of that happens if the zombies are fast.