Right now Fritz is the only pal with a sliding special attack.
Personally, Fritz is by far the most fun pal to play with and the biggest part of it is exactly the sliding attack.
There are other great pals that are at least as effective as Fritz (such as Aska and Ceres, or maybe even Irmgard), but none of them slide. They feel a bit boring to play with in comparison. The gameplay style they provide (a big army is needed and the Hero is supposed to protect it) makes them not as fun to play with. They’re very strong pals though.
With the right setup, Kaiser and Phoebe (and probably others) can be pretty effective as well, and although they provide a similar gameplay style as Fritz (more Hero dependant and without a big army surrounding it) they’re definately not as fun.
Let me be clear that I’m not talking about pal power/strength/effectiveness here. I’m talking about playstyle and fun while raiding.
I don’t know if Flare is looking to create new pals right now, but a new sliding pal in the game would be very welcomed.