It's hard to understand, because sometimes something in the game looks so fantastic, especially inside the caverns, all of the magic effects, the carnival tents at the festival, and many others. But both the videos and most of the game screens can't quite obtain the sharp clarity of Diablo. Not many games are designed with as solid a gameplay platform as the one used in Baldur's Gate. It's truly an amazing piece of work, and allows players to focus on the game, rather than mastering the controls. Click on the 'Cast Spell' icon, then again on the spell to be cast, then once more on the target, and you're doing magic.
Battle is especially interesting.
It's true that real-time battle is often very confusing, especially if you have many units under your control. Spells, range weapons, and other devices take time and thought to plan and use. In Diablo, and Baldur's Gate multiplayer, it's not an issue because a single person controls each character, and can react with the speed and intelligence of a human. BioWare took this into consideration, and created a 'pause' function that can be used to issue orders before battle resumes. It's easy to turn on and off, and allows characters to use their 'quick' weapons, items, and spells effectively and with very little confusion, as well move around the area for the best angle of attack.