Just wondering if the larger paddles with bigger blades are preferable for people who paddle at a slower cadence? On the flip side, are the smaller paddles better for a quick cadence, or is it all just preference?

When my shoulder would tolerate it, I used a large blade and loved it. Now the shoulder prefers the smaller blade. I have never been a fast cadence paddler.

Like the gears on a bike you adjust them for the cadence you want to use.
I have a smaller blade for a shorter boat that allows a faster cadence where using a large blade would hit the wall before I got to my cadence.
Smaller blade is also nicer going into a stiff wind.

Bigger blade size for a smaller person only slows them down ultimately and often results in shoulder injury no matter how good their form. Cadence first.

I got in the stern of the canoe when Qruiser was in the bow with a paddle 1.75x the one I had. The paddle was also too long for her so she was doing a modified sweep stroke with each stroke. I needed a bigger blade to counter her enthusiastic paddling.

I think how hard you want to push towards boat speed has a lot to do with it. Quick acceleration and powerful maneuvering strokes will fit in there too. One part boat limitations. One part personal limitations. 3 parts your personal drive and ambition to push effort.
If you don’t push hard enough with a small blade to note any limitations, stick with a smaller blade. From there, work on form and getting the most out of your paddle. Once you dial in there, and you feel like you’ve got more to give, give it a go.
That said, there’s no reason you have to push hard using a larger blade. The blade is mostly just planted, with the goal of pushing the kayak. If you want to stay in the kayak’s efficient cruising speed range, you certainly can.

What grayhawk said: like a bicycle; big and little chainrings. I always take two paddles; the big chainring with more surface area for downwind and the little chainring with less surface area for upwind. Works great.

I can think of several reasons unrelated to shoulder protection to keep the blade size moderate. Sculling and some ruddering maneuvers it seems to me would be hindered with too large a blade. A light weight paddle is a desirable aspect; a big ole blade counters that virtue somewhat.

But, I must confess the only large blade I ever tried was also not a very good one and I took it back after one outing.

To use the bike analogy, blade size is your front chainring. Paddle length is the rear derailleur.
You can find the “right gear” by experimenting with blade size/shape and shaft length. I have both wing paddles and a GP (Roy Martin built) that allows the shaft length to be adjusted on the fly; great stuff. These are virtually standard for wing paddles; Not sure why they are less popular for touring (other than Werner doesn’t make them). You can go shorter into headwinds, longer for downwind, not to mention adjust for different conditions, kayaks, etc.

I wouldn’t think sculling and ruddering would be hindered. A larger blade can offer more effective resistance for those too.
What a person might experience could be exemplified by paddles from opposite ends of the spectrum. Has anyone ever used the Lendal Powermaster? Side by side, the Werner Ikelos is small. So think Greenland paddle vs Powermaster.
If you are sculling with a Greenland paddle, you can scull back and forth with a good bit of leeway in the precise angle of your blade, and maintain a nice, even, side-to-side sculling motion. The Powermaster will comparatively feel very little resistance slicing through the water, but require very precise blade angle control to achieve a nice, even, side-to-side skulling motion.
So the Powermaster could hinder you if your blade angle control isn’t there, But once it is, you can generate some significant controlled pull with all of that surface area.

Epic at least used to make adjustable length touring blades, l have a foam core touring one of theirs with a range not wing, l want to say Active Tour but don’t quote me on that.

Sometimes improper paddling technique - using just arms/shoulders instead of torso rotation -affects how well you paddle, regardless of size of blade. Secondly, there are several good articles on this website about skills and techniques that address many of these issues. broad blades are often power blades on shorter shafts and used for sprinting, bracing, while longer, narrower blades are good for extended, casual paddling…and then there’s the Greenland style which is a whole new paddling experience in its own right…I’d really spend some time checking out the tips section in addition to all these speculative discussions