I just finished the converted game. I probably have missed some of the conversions, but here's what I noticed much:
* The graphics seems to run smoother (I did not spot any visual improvements - which does not mean they are not there).
* The game got significantly easier due to earlier access to good weapons and to better weapons later-on. This mostly means some of the fights that were "not hard but tedious" got more easy to win and the gameplay got much smoother due to this.
* The higher XP-rewards in Broken Valley make much more up for the cost of reading minds. You'll level much quicker for the first levels. The extra-xp did not seem to have any impact once you met Talana. All in all, this is a noticeable and good improvement.
* The balance of the loot drop has changed a lot, I think. "Normal" enemies do not drop loot as often so you do not have to collect as much stuff. All in all, I did not seem to miss much and the game went smoother again.
* Some "tedious" places have been re-designed (Imps in the Fjords) so you do not fight the same, big, group of the same enemies over and over again.
* The flying fortresses have been re-made. They actually now resemble fortresses instead of bare rocks (once you blasted everything off). They have troops there that make more sense than the groups of two to four guys from the Black Ring. Most dragon shields have been removed, so you can play the thing much, much faster.
You also do not have to weed the entire, large fortress anymore for the armour-sets (see below), so you can "show them the might of a dragon", blow of their houses, kill a bunch of them, kill their leaders and leave. The fortresses are much better now.
* The armour-sets (Scorpion, Archmage, etc) have been moved. Instead of being on one of the fortresses each, the sets have been scattered over the world. This makes collecting much more interesting and believable (and you do not have to weed through 100% of four fortresses anymore).
Also, some of the sets are now found in hidden chests that you could reach with solving puzzles or in side-quests, thus the puzzles have seen a significant upgrade in relevance. That's also good.
All in all, the differences are not that big - but they do have a massive impact on the feeling of the game and makes it better to play. I would recommend the upgrade for anyone who has ED+FoV. I has a slight issue with the conversion, but the support could quickly take care of that (two files were missing).
One possible issue is that the patcher of DKS does not recognise my copy as valid copy of DKS, so it might be impossible to install future patches (which does not seem that bad as I think my gameplay was issue-less).