スマートかは兎も角、一応マシな形に。
空リストや要素数1にも対応。

Haskell

main = putStrLn $ last2 lst

last2::[String] -> String
last2 [] = []
last2 [x] = x
last2 [x,y] = concat [x," and ", y]
last2 (x:xs) = x ++ "," ++ last2 xs

lst = map show [0..5]


output:
0,1,2,3,4 and 5