Lileep is my passion (along with Vullaby) so I feel I must defend it. The abundance of Fighting pokes AND the wide distribution of fighting type moves for coverage (HP on Gastly, Brick Break on a lot of Normal types and so on...) are the biggest weak points for the lovely flower, but they're not the only things that destroys Lileep. Its weakness to U-turn, Ice-type moves, susceptibility to Toxic AND the strong dependance on Eviolite (giving it a fear to Knock Off) are some things that really makes Lileep a difficult poke to play with.
HOWEVER, it can shine if you understand that Lileep is not the average Wall; sandstorm and Stockpile are its biggest selling points. I have swept with Lileep just because my opponent kept attacking me with HP Fighting in sandstorm and let me Stockpile with impunity. With the prevalence of special attackers (Chinchou, Gastly, Staryu) and the abundance of Fighting counters gives Lileep the spot to shine; I mean, like a lot of pokes, good team support (a heal beller and a fighting counter) makes Lileep shine.
Personally, I like a Lileep a little more oriented to Def as opposed to SpD:
Lileep (F) @ Eviolite
Trait: Storm Drain
EVs: 148 HP / 220 Def / 140 SDef
Bold Nature (+Def, -Atk)
- Energy Ball
- Hidden Power [Fire]
This gives 27 Def, 25 SpD and 25HP; after just one stockpile Lileep can handle weak physical fighting moves (unstabbed Brick Break, for example), 25 HP lets it recover 13 points and with Hippo support it's almost impossible to take it down. Vullaby is a great partner 'cause it removes common toxic users if she carries Taunt (Bronzor, Slowpoke and the not-so-common Frillish), AND with Air Slash as Flying STAB it destroys Larvesta and Fighting 'mons who generally have weaker SpD.
It's not anti-meta, but the combo gave me a little success. Maybe if I were better at teambuilding I would've give them the proper support to be a top player :P.