1.Stats: Should Sandslash get a stat boost, Evolution, Mega Evolution or nothing?
+55 to match Ninetales is a possibility.
However, an evolution makes the most sense.
A Mega would need Huge Power to be relevant.
2.Should Sandslash get more abilities?
Tough Claws is a option.
3.Should Sandslash get more moves?
Psycho Cut and Night Slash are options.
4.What additional typing Sandslash can have?
Poison, Dark and Rock are options.