Simplicity is a good thing. It's a virtue. It's part of what made UNIX a success. It's not something to shun or avoid.
Adding features adds complexity and complexity is not free.
Notice how the industry still has't jumped ship whole-sale to Haskell?
It seriously depends what you're doing. As someone put Haskell recently "all the possibilities of advanced algebra combined with all the clarity of advanced algebra".
Simplicity is only a real success if it doesn't throw out the baby with the bathwater.
> Adding features adds complexity and complexity is not free.
And taking away features is free ? Why aren't you programming in LISP then ?
One of the reasons it's not widely adopted is that the features that programmers take for granted, like built-in syntax for mutable variables, are missing, i.e. it's too simple.