I should've been more clear — DSSSL might've been able, possibly in conjunction with later extensions (just as XJAX was not originally part of Javascript), to provide a similar end-user experience in many cases as CSS+Javascript currently does, albeit with very different semantics for the developer.

Not sure it would be better (it probably erred on the side of too much mixing of program logic and styling rather than too little), but it would certainly be different.