RPGs is not 'lightly armed', suicide-bombers are not 'lightly armed', thats just 2 of the most used ammo by "lightly armed insurgents'.
They most certainly are. An F-16 or what not droping 500lb bombs is heavily armed. Howitzer shells pounding a village is heavily armed.
RPG is an infantry weapon, and unless we're talking about RPG-30's, they definitely are light arms and pose no real strategic threat to Pakistan.
Suicide bombings, on the other hand, are politically volatile even if it is a crude weaponary. Such tactics are insidious as it's impossible to guard against without resorting to draconian measures. Again, a conventional military response is nonsensical to that particular threat.