Okay...FWers, this ol' "bully" is going to slay the FW Goliath that you trust in, rely upon and in which you put all your confidence. Just as David was fearless in the Lord (as I am!) and took the battle to Goliath by running full steam ahead toward him with slingshot in hand, likewise I'll be coming at you full throttle (albeit one passage at a time so that y'all don't go spastic, ballistics or convulsive on me), so gird up what little you have left of your mind to deal with God's truth, which you will not be able to do apart from reading your carnal presuppositions into the passages.
Just don't forget what your carnal presuppositions are re a text like Jn 3:16: God died for each and every person in the world to give each and every person w/o exception the opportunity to effectuate his/her own salvation via a "freewill" choice to repent and believe the gospel. So...let's see how this presupposition works out with passages that explicitly speak to God's purpose in sending his own Son into the world to die for "all" men.
1 Thess 5:9-10
9 For God did not appoint us to suffer wrath but to receive salvation through our Lord Jesus Christ. 10 He died for us so that, whether we are awake or asleep, we may live together with him.
NIV
So, your first challenge is to determine who are the identities behind the personal pronouns used in this passage, e.g. "us", "our" and "we". But at the same time, you should also remember that the people behind these pronouns are part of the world for whom you FWers allege Christ died. So...what applies to the people being referred to in this passage must logically apply to the entire world in the distributive sense.
Your second challenge is that God's purpose is clearly stated in this passage. Two things are noteworthy in this regard: A.) God's purpose for these people, stated negatively, wasn't to suffer his wrath (v.9) since they were never appointed by God in eternity to suffer condemnation . And B.) God's purpose, expressed in positive terms (v. 10), is that he did appoint the "we" and "us" to live together with him forever.
And again, if all this is true for the "we" and "us" (who are every bit part of the world that God "so loved" and sent his Son to die for), then it must apply to the rest of the world as well. After all, God isn't a respecter of persons, is He? What goes for the goose works for the gander as well, right? Otherwise, God would not be treating all people equally, fairly and identically which is a fundamental tenet of FWT. What God does for one, he must do for all in order to be just, fair and righteous!
Therefore, if FWT is true, Paul is teaching that God's purpose behind Christ's death was not to appoint anyone whatsoever for wrath but to save all w/o exception since the "we" and "us" in the passage will spend all eternity with God because to this they were explicitly appointed -- and, therefore, by extension the entire world was as well! Universal Salvation is clearly taught in this passage when the presuppositions behind FWT are taken to their logical conclusion and applied to a passage like this.
Have fun, folks....