Though I agree with dereklapp's statement that the term 'simple' is misleading, you can have visually complex logos that are clear and understandable. Using the term 'flat' is worse, as many logos have the illusion of depth through the use of perspective, gradients, shadows, and tapers.

I would suggest that a logo should be developed with consideration of all output possibilities. It should not rely on shading and photographic blurs in its most basic form. It should be be developed completely with lines and outlines and when and if gradients are used they should decay well enough that the logo remains intact and clear.

On the subject of the WarCraft 'logo' - WarCraft is a product. Logos represent companies and brands not their products. Products generally have package design or presentational design. The WarCraft stylized name is part of packaging and presentation but doesn't represent a brand. Blizzard Entertainment has a logo. It is one dimensional and looks great in black and white although it is usually in a light blue/cyan(ish) colour.

Regarding Julian's suggestion that Brooktrout's logo will 'stand the test of time', it is alot less 1990's than the DEG logo but it is still using typeface and colours that may over time find itself outdated. Design is almost always susceptible to obsolescence and may need to be addressed. The colours or the typface may need to be changed to reflect more current appeal in the future. Just think about all those western styled typefaces that were used in the seventies or the cold sans serif typefaces that were used in the eighties.

What a great topic though. BTW, I am not a graphic designer.

Jay