Really it doesn't take much to neutralize individual zombies. But in droves, you can quickly get overrun.
But it did bother me that T-Dog essentially got devoured alive by just two of them. Most people could fend off against two limping zombies. It's not like they're going to fight you beyond flailing, and if you're already bit, you don't have much to fear. They're not superhumanly strong. If anything they should be easier to fight than ordinary people, since they don't seem to try to evade any attacks.
Would like to hear you tell this fairy-tale story when Dale looks at you after his stomach got ripped up
(just joking round, mkay?)
Maybe he was very weak but its hard to rip a human stomach with just your bare hands. There are also other scenes where humans got ripped up easily.
I think zombies are not all the same. Some seem to be smarter/stronger than others.
Also there is a reason why you wont get on a zombie bare-handed (at least if you can evade the fight). A zombie is like a wild animal. He will attack you no matter what. You cant even be sure about the way he will attack you. If you would get bitten or scratched its nearly over.
So I would say its better to kill them without givin them a chance to get to near.
The way Ricks group got trained by him (and Daryl) is very effective. Their battle formation is close so they wont be suprised even against dozens of zombies. They use their advantages like killing off zombies through a fence or distracting zombies so they part up instead of staying as a horde making it easier to pick out 1-on-1 situations (which is VERY important since its hard to kill more than one zombie at a time).
For me its just to show how much this group has grown accustomed to this survival-situation they're in.
I dont even think the show makes the zombies look harmless. It was always the situation that decides the danger.
It was always the way it was stated from the very first episode:
"They might not seem like much one at a time, but when they're in a group all riled up and hungry, man you watch your ass".