I think the key question is what you mean by streamlined. (and I'm the author of S&W so you know where the bias lies).

LL is more streamlined in virtually every way than S&W, but so is C&C. In fact, I think C&C is more streamlined than either LL or S&W. So since you don't like C&C, that raises a question about what you mean by "streamlined."

S&W is pretty wonky in that virtually no task uses the same die roll. Turning is on 2d10, thieves use percentages, etc.

The S&W rules present one "default" pathway, or set of rules, which are my interpretations of the various ambiguities in OD&D, and I usually note where there's a difference or an alternate interpretation. Thus, there is a simple, easily learned game that is, however, surrounded by a cloud of possible alternate rules for when you want to do some house ruling or experimentation. It expands.

S&W Complete is based on OD&D right before they created AD&D, so it's very similar to AD&D but has some significant differences here and there in unexpected places. Plus it doesn't have the vast array of supplemental possibilities contained in the AD&D DMG. Neither does LL, so no matter what you choose in terms of LL vs S&W, still use a copy of the 1e DMG as a source of non-official possibilities. Ignore the rules in it unless you choose to use them, but there is an incredible amount of inspiration in there.

Both games are very strong - you can't really go wrong with either one.