The ED-209 was a chicken walker mechanoid that didn't function properly. It was in the movie to poke fun at how certain US companies release products. There are many things overtly wrong with the ED-209. It is not programed very well. It seems to lack processing power for its AI. There are clear vulnerabilities in overt places. All of that is true, and more. However, certain things people point at as flaws, are not necessarily flaws.
The one that comes up often is that the ED-209 can't use stairs, that this is a huge design flaw. However, looking at it, it was never meant to go inside buildings or use stairs. The "ED" in ED-209 has two potintial meanings. In the original movie it is said to mean "Enforcement Droid". In the RoboCop live action television series they say "Enforce and Defend". Either way this machine was clearly meant to be on the streets, or to be used at key locations. It was not meant to be a bodyguard for an individual, nor was it ever intended to let loose in an office building.
Was the ED-209 a poorly built/designed/made machine? Absolutely. However, it is also used improperly when we see it in the original RoboCop movies/television series.
