While there certainly were bits in 3e that were individually simpler than the corresponding bit in 4e, there's just no comparison when it comes to the complexity of the whole. In part, precisely because 3e did use different sub-systems or structures to make some things simplistic and others complex - doing so adds to overall complexity.
5e is heading the same way. Overall, it's modular approach is a recipe for levels of complexity D&D has never before seen. But, given a DM with mastery of that complexity, a given campaign could be paired down to a very simple sub-set of that complexity.
I'm not sure that's a big distinction, but OK, if you prefer 'more streamlined,' that's fine.
That 'streamlining' of common mechanics and consistent structure was certainly gone from the playtest, and would seem to be at odds with the modular approach, but bounded accuracy is obviously going to try to deliver on the scaling issue (which was largely illusory, the 4e 'treadmill' being rather transparent, anyway).
Simplicity is appealing on a number of levels. Personal preference, ease of DMing, shallow learning curve, faster play, etc, etc... Varied complexity within a system delivers some of them, like personal preference, player-by-player, but not others. Modular complexity, likewise, it gives the DM a lot to master and a lot to do, but if he puts in the effort, he can deliver a simpler experience (or a more tailored level of complexity) to his players.
I think a critical thing that 5e isn't focused on is that simplicity is much more important to the new player than the experienced one. Experienced players may or may not like complexity, but they can deal with it, new players can be put off by the steep learning curve. 5e isn't really targeting new players, though, in it's attempt to re-unite the existing fan-base.