I said "mostly"!
Well, I tried Exiles. Everything good, except dialogs. Need to enter every key reply manually simply killing me! I can tolerate IFs, but it's pretty much everything where keywords are really in place for me.
Avernums, on the other hand, have exactly the same content as Exiles - only somewhat newer engine, and menu-driven dialogs. Much better, as for me!
And I cannot say, of course, how close Avernum to Exile overall, but Exile I and Avernum 1 had exactly the same plot and initial dialogs, and pretty the same layouts and NPCs for first city, first raider base and overall map in first sector. I wasn't in more distant lands in Exile, so I cannot compare them more.