As you’ve probably discovered in your research, the SL uses a joy stick for modulation and pitch (with the added benefit of being able to do X and Y).
Some keyboard players may want the traditional mod and pitch wheels.
As a MIDI guitar player, I have no real preference for wheels vs joy stick.
The joy stick has a firm spring tension on the horizontal axis for pitch. Releasing the spring (underneath the unit) allows the vertical axis for modulation to be placed, where it remains, as one would expect with a mod wheel. Otherwise, the spring loaded vertical axis returns to the center when released.
Being an old geezer from the age of vinyl, I also don’t use the pads. Reviews say they’re kinda stiff.
I remain excited at having the SL MKll 25 at my disposal: Excellent control surface with Automap, and keys for entering keyswitch notes when using sampled instruments.