I would *highly* recommend going beyond the snugli/bjorn concept of babywearing. There are carriers that are FAR better for everyone involved. The biggest one I would recommend is the Ergo. It has a broader base for baby's pelvis than the Bjorn (which gives them more ergonomic support b/c they aren't "hanging from their bits and pieces"), and it's a DREAM on the adult's back. If DS and I were still in "wearing" mode, I could easily do it still, and I'm 5'3" and he is over 38" and 34 lbs now. A back carry, of course, otherwise his feet practically kick my shins, LOL.
The Ergo with a back carry took up about half of our DL day last October (the sleeping picture was an anomaly), but I can't post a picture b/c my sister in law is in them and I don't have her permission to post her online.
As you can see from my avatar, DS was on my front, facing me, most of our first trip in '05.
Having a kiddo in a sling or carrier doesn't mean they don't see anything. Quite the opposite, actually! They see more, they are up higher, so they are seeing the sights, NOT people knees and bottoms.

And if they are facing you, they are interacting with the people behind you, and see all the sights, just after you. Have you ever taken a train and sat with your back to the front of the train? You actually see MORE scenery like that....I don't know how that works, but I love to sit backwards in a train b/c I really get to savor the scenery that way. DS absolutely adored interacting with the people behind me, and I think the people did too, b/c they could make silly faces at him without me seeing them, LOL.
IMO it's not sheer size, but it's development that comes with age, that makes it OK to go from a reclining stroller to an umbrella. The little ones just usually don't have the stamina to keep themselves upright as they need to be, in an umbrella or jogging stroller. IMO.
It's so fun to start DL when kids are little. You get to see them develop and change...on our first trip, DS just nursed and slept through POTC and into our lunch. Last trip, he sat on the seat and stared, wide-eyed, through the whole ride. He wasn't frightened, but he chewed on my shirt as some sort of comforting device (something he has never done before or after) to keep himself feeling safer, and LOVED the ride and is almost desperate to go on it again this September.

I cant' wait to see how he reacts to everything this year (though I'm slightly concerned he'll have a bigger fright reaction). I only wish we'd started as young as your kiddo!!!!