Change the player-unfriendly trap mechanics in BG.
An RPG game without traps can hardly be called an RPG game. BG does have vicious traps awaiting a careless foot, but the implementation leaves to desire better.
In order to avoid springing a trap the thief has to crawl slowly, stopping every several steps to detect a potential threat. Worse yet, ONLY the thief can seek them out (I wouldn't really consider Detect Traps spell or the monk). It isn't too bad when you already know what trap is where, but exploring the area for the first time becomes a tedious chore, because quite often a trap is well capable of killing the victim instantly.
Yes, there are workarounds - press CTRL-4, save and reload, or install "No Traps and Locks" tweak, but there is no option to play without metagaming yet dynamically. Some may argue that exploring newfound dungeons should be slow and cautious. Agreed, but definitely not as slow as what we have.
Few months ago I had made the "Passive Trap Detection" tweak, to help me out with playing BG1 part of BGT. Whenever an active trap sees a PC within 15' range (half the vision radius), it displays "Trap Detected" string over self every 2-3 rounds. It doesn't become visible - i.e. red - only warns the player to pay attention here, so you still need to get your thief over there to detect it with the "disarm traps" skill. Once detected, the string changes to the trap's type, e.g. "Arrow Trap Detected" or "Fireball Ward Detected".
The logic is pretty straightforward - a seasoned adventurer ought to notice that something is amiss in front of him. He/she doesn't instantly know what exactly, but is aware that the place is dangerous and more throughout examination is called for.
I have tested this tweak through the entire BG1, and have found it to be near perfect gameplay-wise - the thief remains as vital for trap surviving as before, but the game can be played more smoothly, no frustrating delays to scout ahead the entire area before proceeding to kill its inhabitants without a fear of sudden death. The ability to know trap's type also allows to set it off by sending in an appropriately prepared character, if thief's skill is not high enough to remove it - indeed, disarming is more difficult in DnD. Now I only need to fix a couple of small bugs and it is ready to go.
That is what I wish to see in BGEE - trapped regions and containers give off some kind of warning when somebody approaches them, and reddened traps also provide information about their type, allowing to prepare for them.
My tweak is purely script-based, and requires to be installed as late as possible due to some limitations, but if made on the engine level, it should be 99% mod-friendly.