ToSC is counted as being vanilla, its an official add-in expansion. Vanilla means base game, plus any expansions and official patches.
Your criticisms of BG1 are a matter of taste, and don't make it a bad game. Many people who played BG1 before BG2 consider it to be superior to the sequel, for the very reasons you disregard it, like being able to simply explore the areas across a map. As for plot pacing, those areas can be ignored entirely.
Just like how in BG2 you can ignore most of the areas around Athkatla and seek out Imoen, and just like how when you seek out Irenicus you can ignore Sahuagin city and much of the Underdark, if plot pacing is really that important to you.