Well engineering is a person building things and figuring out how. (Bill Nye doesn't make any sense to me comparing it to evolution since evolution is about natural selection - to me engineering *is* creation - but that's just my belief. If you wanted to argue microevolution is also engineering - i.e.: creating a new dog breed by mixing labradors and poodles - I would agree, but creationists I know still believe in microevolution as in my example, just not macro).
But, let's leave aside the debate over that, and look at this the way a kid would. As noted, catering to the original, 4-6YO demographic, it makes sense. However, one of the things many 2-3YOs love to do is bild things. The big question is, do they know *how* they are building? Indeed, do 2-3YOs know that they *are* building thigns?
Engineering, to me, is creation, as I stated. This means that if they're going to focus on engineering, they might (bad pun alert!) be able to get away with the very building blocks of it. But, that would be things like, say, putting things on top of each other. Gravity could be used to show that, "If you put that block too far over the edge of the block under it it will fall over." Indeed, that in itself could be a very interesting idea. "Watch how you care that bundle...will thigns fall out of it?" (I wonder if, in the upcoming street scene where Baby Bear gets ice cream on his new white shirt, that is mentioned. An ice cream cone is a very unwieldy instrument for carrying somethign that melts.
I heard of a 3YO in church once who did a little experimenting that could be called engineering, in fact, which could be used on Sesame Street. She was coloring during the worship service. She tried to put her crayon on the ground for a moment while she used nother - it began rolling down the aisle. She picked it up and turned it a little ways - it still rolle. She kept this up until she laid the crayon almost parallel with the aisle and it didn't move.
Yes, she was doing more problem solving than building, but part of building is problem solving. The people who repair our infrastructure when we need it (or just who repair Midwestern and Northeastern potholes in the springtime) will be starting with these simple concepts like figuring out when something will roll and when it won't, when somethign will topple under certain conditions and when it won't, that sort of thing.
Sesame Workshop can do things like this and I think help our children learn, but only on the level of thigns that they do - put a block on top of another, try to keep a crayon from rolling, etc.. They might be able to move from that to other things - they might even be able to move to things like why a baseball bounces differently from a football (though that's more for older kids). However, I think the problem witht he engineering thign is not that they are doing it but that they are not realizing that a 2-3YO needs to grasp certain concepts before they can grasp other concepts.