Meggan during Ellis run was actually very nicely handled. It expanded on her elemental powers, including the realisation that someone who can, on top of all the standard elemental powers over fire, air and water etc, control electricity compltely just by ASKING it do things, can essentially disable any electronic system going.
Also the fact that she LOVED her powers, Kitty comments that she's never seen anyone enjoy using their powers more than Meggan does.
And the punching scene is brilliant, to the extent I can still recall the phrasing from memory;
"Captain Britain and Meggan are Excalibur's strongest members; Being hit by either of them is akin to having a fridge freezer dropped on your head. Being hit by both at the same time is like being punched in the face by God"