Well I've just spent the weekend and tonight getting 16 module blueprints and 4 weapon blueprints and I have to say I really enjoyed doing it and found it to be a lot of fun. So much so that I have now decided to get all of the Guardian weapons and modules on offer at the moment whereas before I wasn't planning to.
However, I won't do it all at once as that's not my style of playing as I prefer to break up my activities with different ones.
I may even on occasion head out to the Guardian structures to do the activity even after unlocking everything because I do find it fun.
It takes me on average about 30-45 minutes per site as I don't try to rush it, instead I just enjoy the experience, shooting all the sentinels and collecting all the data and Guardian materials. Also, I never re-logged at a site (I've never liked re-logging or board flipping), instead I flew to a different one after getting a blueprint, fully scanning systems along the way.
So sorry, but I do really enjoy the Guardian mechanic. Just be thankful I'm not the one doing the streaming though as you would get bored watching me before I got bored of doing the activity.