I still play that game a couple times a year. Just the other day I went through it and created what I called the "Gimp Group", one made up of a Monk, Barbarian, Ranger, Druid and Sorcerer. (I still couldn't bring myself to play the most useless of all classes, the Bard, even though this was the Gimp Group.) I twinked them out with the cheat codes and bought them all the best starting gear, etc.
I ran it using the Circle of 8 mod pack, which fixed most of the bugs in the game and added a ton more content (www.co8.org).
Anyhow, I got the guys all geared up and set out to the moathouse---and was killed in the first wandering monster encounter. It was pathetic.
Granted, the TOEE game is essentially a game of combat, not RP. To the extent the characters are good at combat, they will be more successful. My standard group in playing the game is 2 fighters, wizzie, cleric, thief. Sometimes not even the thief. I usually blow through the game with no problems.
In my tabletop games, we forbid all prestige classes, and any experiences we have had with the above mentioned Gimp classes has turned out horribly. Maybe it's our lack of skill in playing those classes, I don't know. The only one that ever worked out ok on the tabletop was when a player rolled up a barbarian, and so in spite of the player's ineptness, the HP helped him survive.
Anyhow, my question is this: in a straight-up combat oriented tabletop game, without prestige classes, are the core classes head and shoulders that much better than the my Gimp Group's classes in your experience?