Did they re-record the voice lines aswell? Or some new dialogues?

[Smookio]

Title. I finished Oblivion back around 2010 or something. I remember nearly everyone having the same voice. (a total of 5-10 voice actors?) Say you randomly meet a dark elf and 10 minutes later same guy voices the bartender. Did Bethesda do something about this?

[space]

it has both new and old vo

[Malus Lupus]

They left all the original voice acting for some and used new voice actors, including quite a few from Skyrim, for others. When originally released they used the same voice actors for a lot including races to save space on the CD due to both the physical capacity of the disks plus old sound compressing available at the time. Now each race has separate voice acting. Lucian Lachance still sounds the same.