I can see many people agreeing with you that Taillow is better (to be fair he is) but Spearow does have some advantages. 16 speed isn't too bad in LC. Apart from Drill Run, Pursuit is the other edge he has over Taillow, although I guess it can be situational.
As you said Sniper is outclassed but it could come in very handy: a simple critical hit may not be enough to take down some walls.
This is the set I use on a (mediocre) hail team as a revenge killer and something to maim fighting types:
Caw (Spearow) @ Choice Scarf
EVs: 36 HP / 200 Atk / 36 Def / 36 SDef / 200 Spd
- Drill Peck
- Drill Run
- Quick Attack
I believe this gives him a speed of 24, enough to outpace +1 Scraggy and take him out with Drill Peck, or U-Turn out to something that checks it better (in my team's case, I use Sandshrew, who isn't a counter but has decent physical bulk)