what they did right: great implementation of D&D 3.5 combat, cool engine/rendering stuff (2D+3D).
what they did wrong: follow that bad module verbatim.
What ToEE did right:
1.) TURN-BASED COMBAT NOT REAL COP-OUT WITH PAUSE, HELLO
2.) GREYHAWK CS
3.) Silkily animated characters moving around on luscious isometric backdrops.
4.) Intuitive radial menu and clear UI panels with full ruleset and breakdown of events reviewable
even during combat.
5.) Solid framework for C&C dialogue (symbols for bluff, intimidate, gather information etc.)
6.) Support for larger parties than IE, plus enchanted enemies and summons follow you from area to area
7.) Detailed, nuanced and precise movement rules.
8.) Unique animations for critical hits and utility skills
9.) independently targetable spells (Magic Missile)
10.) AoE of spells can be seen before casting
11.) Impressive build variation even with a level cap of 10
12.) Initiative prioritizing during combat
13.) Spell effectiveness changed with environment (e.g, Fireball doesn't work too well in Water Node, makes sense)
14.) Party alignment-based opening vignettes
What ToEE did wrong:
1.) Atari as publisher (read about how they hamstrung them)
2.) Failed to implement factional behavior as per module
3.) Awful pathfinding
4.) Horrid node lag (almost game-breaking)
5.) Terrible voice-acting and forgettable music
6.) Almost non-existent C&C
7.) movement in modal stealth TOO SLOW
8.) last but not least, BUGS
In premise the game is full of win but it failed epically in execution. Even so, Obsidian would do well to use
what ToEE did right as their prime model, though I see they chickened out on turn-based combat which is kinda sad.