I typically finish a lvl 24 strike in about 13 minutes, yes I run through it as fast as possible. I almost always get two blue engrams each time at the end. So let's just say I get about 6 blues every 30 mins and the occasional purple. To have someone fight all the mobs (even just the high-lvl ones) is dumb. And besides most strikes have an area where you have to stay and fight anyway so there's that if you're not down to run through with me. All in all, I see it more effective to run through the strikes when trying to gain anything other than exp.