One thing that comes to mind is that looping is limited to recursion in scheme. This becomes quite coumbersome IMO since it is a pretty important thing. Writing named lets for simple things is not anyone's preferred way.

It is however pretty easy to implement something like racket's for loops on scheme using lower level macros, and there are some available.

Implementing something like common lisps iter is actually not very hard, and even improving upon racket's for loops is far from complex.