Well, i'd do anything it would take to try influence the direction of the people 
No matter what the cost!
Question though, do we keep our old brain/thoughts when we live in the selected time-period or do we start "fresh"?
When we incarnate/borne into this life we start with an auto-induced amnesia. All memories are there but we don't recollect. Some do remember, some remember well, some never even wonder. It all depends on what we came here to do individually. In this life, remembering suits my purpose. For you maybe it does't so you don't even think about it.
However, I found out that our childhood hobbies or inclinations, our teenage preocupations, our relationships mirror what once was. Even phobias reflect past traumas etc. The people you have relationships with (meaningful ones) more likely than not lived other lives as well together with you (maybe different roles).
There is no point in remembering unless you have the opportunity to finish unfinished business. Remembering everything would drive you insane so you only remeber what you NEED to remember.. IF that.