Yes, that basically means the board will be hard to control, either in terms of initiating slow speed, skidded turns, or keeping speed under control when carving. Taken to all extremes, a very stiff, long board, with a large sidecut radius will require a delicate balance of finesse and manhandling to make skidded turns. Likewise, it will take a significant amount of skill and aggressiveness to make it turn tight, with a controlled speed when carving.
The most difficult board I've ridden to turn at slow speeds has been an Oxygen Proton 178. An alpine deck, it was quite stiff, and exhausting to ride with hardboots if the day demanded skidded turns. Skidding turns felt like riding a 2x6. It felt sluggish when carving at slow speeds, too...but there was a magic speed when it came alive and vaulted from carve to carve. THAT's where it became extraordinary.
My current ride is the most demanding (and the most rewarding) board I've ridden at speed. It's a Coiler 182 new school race, ridden with plates and hardboots. With a 17-meterish progressive sidecut, it will jetison down the fall line at the slightest whiff of intrepidation, but will also pull mind-boggling G's and ass-to-snow carves when aggressively (and correctly) powered. It eats ice for breakfast when I arrive on-slope, on time, and can deliver the correct balance of finesse and power. It's unbelievable, really, but certainly not something I'd set a beginner down on.
BTW, I love seeing some of these old boards mentioned. My first board was a homemade plywood deal, painted to look like a Burton Backhill in the mid-80's. I didn't have a Black Snow (or similar deal, I forget) until the late 80's. I didn't get my first Burton until 1990!
Yeah, baby, that was cutting edge and extreme...and I had hair!!!