It seemed WAY too easy...

It just doesn't make sense that a diabolical organization on the scale of Dr. No's operation would know better than to put such an air vent in a top security cell. True, it was electrified, but Bond seemed to disable it pretty easily.

Surely the filmmakers could've come up with a more convincing method of escape with a little thought.

In the movie Bond just had his dinner conversation with Dr. No with the latter's offer for Bond to join SPECTRE. It ended with Dr. No being angrily disappointed by Bond's nobility and hatred of organized crime. That's when 007 is put in a cell, which he quickly escapes from (once he awakes) and uses the huge air vent passageways (or whatever) to locate the control center and overload the nuclear pool reactor, destroying Dr. No's entire operation. In light of this, it doesn't seem like Dr. No wanted Bond to escape.

It's still a great movie; I'm just nitpicking.

They'll even have those air vents connected to prison cells that can fit a full grown man or woman 300 years in the future, as seen in the Star Trek episode "Dagger of the Mind."

Yes, residential AC ducts are too small, and commercial ducts are often big enough but would pull loose from their flimsy supports under the weight of a person. Even if they would hold up, they are made of thin sheet metal and the loud banging of someone crawling through them would alert anyone else in the building that something was going on. And the grates in real life are always held on with tight screws, so an escapee would have to be carrying a screwdriver to get in, but wouldn't be able to get out the other end (at least not quietly) because the screws would be unreachable on the other side.