This is a bit of a long list so I apologise, but I had recently come across this thread after I had started playing one of the greatest RPG games again :P So I had to sign up and post my thoughts also I know some of these may already have been suggested but if they have its because I agree with them:
-
SDK - I totally agree with having a SDK, I don't know if it would be possible but some of the greatest content can come from the user base and always creates such a great community where people are sharing tips and such and generally improving the game in many different ways.
-
Spell bar / Hotkeys - The idea of this is to have something similar to most rpg games, just a bar that has specific keys bound to each block such as the number keys where spells/abilities can just be dragged and dropped making spells a lot easier to access but the problem I saw with this is the UI could get a bit crowded, but if you made a similar way of minimizing the bar (if there is one) as with the current UI it would mean that its always easy to access whilst not being in the way. (The way I visualise this is like not the hotkeys that cast the spell, but they just swap the spells around. For example: I press 1, it allows me to use restoration when I right click, but if I press 2, I'm now able to cast fireballs).
-
Compare Item Tool tip - Just a little tool tip when you highlight an item so you can compare it with what your currently using.
-
Multiplayer support (or at the very least, LAN) - Not a necessity but I liked the idea of taking on the story with friends and having to bail them out all the time (come on, we all feel were the greatest when were playing, having downed a mob that was giving you trouble :P).
-
Pin windows - There has been many times where I've accidentally moved the minimap so it would be handing if there was a way to pin it to the UI so it can't be moved until you un-pin it.
-
Continue at the end - I know that all great stories generally must come to an end, but it would have been nice to then just be able to explore with your original abilities, find those items that you wanted, or just play around as a frog. :P
-
Auto pickup of teleport stone - Not really sure how this could be implemented, but there has been loads of times where I've accidentally walked off without my stone only to have to go find it. xD
-
Further camera angle - Not really something I want but on occasions its nice to see a bit more of where your going.
-
Scroll map - On the main map it would be nice for the mouse wheel to be able to zoom the map instead of having to press the buttons.
-
Windowed Mode - Pretty self explanatory. :P
--BUGS--
-
The way the skeletons are summoned - I'm not sure if this is a bug but when you spawn skeleton, there is the odd times where you want to summon them again just a little further as there may be some mobs there, and if you are able to spawn more than one it will generally just destroy and re-summon the latest skeleton as opposed to destroying them in the order they were made.
And finally! (Sorry for the very long post xD)
-
Weight difference - In the last floor of the catacombs during the first part of the game (Freeing Mardanius) there is a few chests dotted around the outside of the center story part, and when they are open instead of being 600 units of weight they drop to 0.
Anyways thanks to whoever reads this post as I know its probably taken some time to read :P So these are my suggestions, oh and before I forget, GOG.com is a very good suggestion for distribution
You have no idea how much I'm looking forward to this re-release :P