But, many R tools are already vectorised, so your shift from lapply() to mclapply() is about as fair a comparison as claiming it's "just" a shift from python's builtin map() to pool.map(). Anybody can play this game, and it's not helpful. I've been using+teaching R now for nearly seven years and the number of times I've used lapply can be counted on one hand.
I use sapply all the time to transform data all the time. It tends to be less code (no counter, no output initialisation ) and easier to follow if that style is familiar.
So there is a lot of rewriting to get things to work on parallel in python compared to R.
In R you just replace lapply with mclapply.