DoomBot said:

What kind of changes were needed or made for the other two movies?

In terms of colour, The Two Towers and Return of the King official blu-rays have blanket green tints over them as well, though they're a lot more subtle than with Fellowship of the Ring, so the regraded releases correct that.

In terms of image dynamics, there are no changes whatsoever, I think the official blu-rays of TTT and ROTK are perfectly fine as they are in that regard.

In terms of editing, there will be no changes to TTT and ROTK in these two 25gb releases. I have in the past created an edited version of ROTJ though that cuts out the whole scene with the corsairs with PJ being shot by Legolas, I felt it took away from Aragorn's appearing with the army of the dead later on during the battle. I also cut the bit with Aragorn beheading the Mouth of Sauron, it didn't happen in the book, the Mouth of Sauron was allowed to leave unharmed. Aragorn would never do anything so dishonourable as kill an emissary under Parlay, I do not know what PJ was thinking there. I could release this edited version as a 25gb release as well but i'll have to see whether there is any interest.