I can offer some personal experience with Sassafras. Years ago, I was lucky enough to purchase some milled 5/4 boards from a fellow paddle maker located in Ohio. Since then it's been a challenge to find quality stock in my local area. I've made a bunch of paddles from it. The designs were all based on historical samples from old photos or surviving museum pieces and most featured some variation of a "Northwoods" style grip.
I've used all these paddles for everything from day use to heavy-tripping. As long as you are aware of (and appreciate) the flex, sassafras can make for wonderful solo paddle.
A fellow at my cottage who comes from a racing background hated the whole concept and feel of flex in my long sassafras blades, but he was a bow paddler used to short & rigid bent-shafts and the sit-and-switch technique.
It will definitely have more give and flex compared to cherry and is much lighter in the hand then a comparable paddle of ash. Sassafras does have an open grain structure like ash, but my personal experience is that it sands quite smooth so feels great in the hand. It also has great rot resistance (unlike ash) so doesn't need to be overly coated in sealants.
But like any other one-piece paddle, the maker needs to select wood stock with the proper grain pattern to maintain strength. Perhaps particularly so because Sassafras can be quite brittle. It also has less impact resistance so it will dent a bit easier if things pound against the shaft or you rub heavily against the gunnels. A while back at the end of a solo trip, I used two paddles tied to the center thwart to form a temporary yoke on my 14' Chestnut (about 65 lbs). One paddle was maple the other sassafras. When I flipped the canoe onto my shoulders and the weight of the boat rested on the paddles, the shaft of sassafras paddled cracked. It's been my only "in-the-field" failure with the wood so far. None of them have failed or cracked during in-water use.
Overall, it is still my favorite wood for paddle carving. On an aesthetic note, the wood also shades well with pyrography. I've decorated a few of the paddles with some double curve motifs...
If you can get one unfinished, you might be able to personalize with some wood-burning designs too!