The thing is that the way the game(s) implement the 2.x D&D rules makes DEX the most important stat for a tank. The best tank in the first game is Shar-Teel, the Chaotic Evil female warrior. She has a low CON and a medium STR but a DEX of 18. With a tower shield and heavy armor her AC is amazing!
This is also why I always equipped whichever second frontline tank I have (me, or say Jaheira with Ankheg armor, tower shield and shimitar) with the gloves of DEXTERITY found on the way to the Gnoll fortress (gives you DEX 18).