ya the dragon age rpg has allot of good things greenronin did a great job also they released the rules is a stand along set of books called fantasy a,g,e, witch is the rules fromdragon age with out the setting.
besides the fantasy and modern age system from green ronin be good to look at for how to handle the things already mentioned
id say the only real thing from another rpg that may be useful in stargate with it being more cinematic action would possibly be the intrusion rules from cypher core by monte cook games. what it dues is allow players and gms to interrupt causing a event