The WG1 charter says "Self consistency is an important objective, which may require adding new features." Scheme has three sequence types: lists, strings, and vectors, but the support for them is not consistent. Lists have the most support, strings and vectors have much less, and inconsistently so. I propose providing the following procedures, some of which are R5RS, some R6RS, some in various SRFIs, and some new:

Type of procedure	Lists	Strings	Vectors
Basic constructor	make-list (SRFI 1)	make-string	make-vector
Variadic constructor	list	string	vector
Copy constructor	list-copy (SRFI 1)	string-copy	vector-copy (SRFI 43)
Basic predicate	list?	string?	vector?
Sequence length	length	string-length	vector-length
Element access	list-ref	string-ref	vector-ref
Element mutator	list-set! (proposed)	string-set!	vector-set!
Map function	map	string-map (SRFI 13 extended)	vector-map (R6RS)
Map side effects	for-each	string-for-each (proposed)	vector-for-each (R6RS)
Convert to list	---	string->list	vector->list
Convert to string	list->string	---	vector->string (proposed)
Convert to vector	list->vector	string->vector (proposed)	---

In summary: 33 procedures, 23 in R5RS, 2 in R6RS, 2 in SRFI 1, 1 in SRFI 43, 1 in SRFI-13 but extended to take multiple strings, 4 novel but obvious.

I further propose that the "map function" and "map side effects" groups should be specified to implicitly truncate all sequence arguments to the length of the shortest sequence.