This passage occurs in the Narrative Lectionary, Year 4 (Most recently Nov 2013). A portion of it also occurs in the RCL, Year C (Proper 23).
Summary: The Hebrew here definitely accentuates and expands the meaning of Jeremiah's words. Maybe because it is Christ the King Sunday, I am thinking a fair amount about God's sovereign title (Lord Sabbaoth) as well as the meaning of "plans" when it comes to God. The Hebrew reveals that God is sovereign but in some more terrifying yet amazing ways than we thought possible.
צבאות ("Sabbaoth"; "Armies", "Hosts"; 29.4): The NET translates this, "God of Israel...who rules over all." While such a title does justice to the Hebrew's designation of God as all powerful, I think taking out the clearly militaristic language at that juncture is unhelpful. The purpose of this title here is a reminder that it is God who has sent them into exile for God is the ruler of armies. This is a horribly uncomfortable reality for us, that somehow, through all the violence of human warfare, God reigns supreme, working not just against but even through war. I struggle with this greatly.
הגליתי ("higlaytee"; "send into exile" in hiphel; 29:4) First point here: Jeremiah uses the first person here in his speech for God: God says he did this. The second point here: The root of this verb means to uncover. In a strange way, to sent into exile is to be uncovered. Removed of our previous religious moorings and culture, we discover who we are in profound ways. Yes, we ultimately discover ourselves in relationship, but a certain learning also comes from separation.
שלום("shalom"; "peace"; 29:7) Last week we read that Isaiah prophecies of a prince of peace (Jesus). This week we hear that God intends to make people prosper, but it is actually the same word. Again, peace in Hebrew is a much broader word than simply a truce!
מחשבה ("makhashaba"; "thoughts, devices, or plans"; 29:11): I am always worried about the word plan in the Bible. It can quickly make both humans and God into a fatalistic machine. The word translated plan here can be mean plan, but it can also mean thought or device/plot:
NRS Psalm 92:5 How great are your works, O LORD! Your thoughts are very deep!
NRS Isaiah 55:8 For my thoughts are not your thoughts, nor are your ways my ways, says the LORD.
NRS Proverbs 16:3 Commit your work to the LORD, and your plans will be established.
NRS Lamentations 3:61 You have heard their taunts, O LORD, all their plots against me.
As the TWOT indicates: "The basic idea of the word is the employment of the mind in thinking activity. Reference is not so much to "understanding" (cf. bi^n), but to the creating of new ideas." What further attests to this is that the LXX translates this as λογισμος, which means thought or reason. I do not disgree that God has plans for the people. In this case, Jeremiah has very clear prophecies about 70 years. But the OT word for plan in many cases means something softer than "calculated plan" and more like "creative and reasoned thoughts" that have as their end peace and hope.