No, the parens don't constitute a barrier of any kind, really. Reading lisp fluently requires very consistent indentation, though. Then you see where an expr starts and where it ends (with nestings and all) without counting any parens whatsoever.

When writing lisp your editor should help you at least a bit to make things enjoyable. They can help a lot, but doesn't have to help much; I found for myself that if the editor just highlights matching parens, I'll be very effective.