Ray Dillinger writes:
WG1 was required to produce a standard such that "any working WG1 program is also a working WG2 program" and that forbade developing a simpler semantic model of anything that WG2 is making complex. WG1 was not to simplify anything that would remain complex in WG2's dialect, nor to unrestrict anything that would remain restricted in WG2's dialect.
In other words, WG1 was expressly forbidden to "remove restrictions that make additional features seem necessary" which is IMO a clear statement that though it has much in common with earlier dialects of Scheme, the language we're working on is not, in fact, Scheme as we have up to now understood it. This relationship with the previous Scheme philosophy repeats one of the design flaws that caused so much controversy with R6, although the effect on the standard produced has not in this case been nearly as pronounced.