Did the person that told you to change the takedown pin give you a reason why? I would curious to know. I can't think of a reason why you would have to unless it walks out while you are shooting. As far as the trigger goes, shoot it and see what you think. Generally AR triggers are a crisp 7 or 8 lbs...lol. If the trigger is to stiff or gritty you can try the 15 minute trigger job found on this sight or buy a drop in from the numerous trigger makers. I have a Jewel trigger in mine and love it.
The only thing necessary for the triumph of evil is for good men to stand by and do nothing.