Although you had some very valid points, I would like to mention why people use Gligar:
 
1. Common
It is a COMMON!!! How can you get better that that, that is great!!!
 
2. Fighting
WIGGLY KILLER!!! Easy way to kill Wiggly with a common.
 
3. Moves
Picture this situation, oponent starts with Jigglypuff, you start with Gligar. First turn, attach DCE and do slash, doing 40 damage (due to weakness) Next turn, he attaches a DCE and does pound. You kill him next turn!!! (even if he evolves into Wiggly). I know he could do lulliby, but how cool is that!!!! Kill Wiggly turn 2!!!! Bonus is the ability to attack 1st turn with both attacks.
 
4. Retreat
or lack of one. Nuff said.
 
5. Resistance
Resistance to fighting. Even though this resistance is common, it is still usefull for those Haymakers that still use Hitmonchan/lee.
 
So all these reasons basically sum up why many people play Gligar.
 
Professor Firestorm
Firestorm Pokemon Labs
 
m527@home.com