Actually, they had consistent world-building throughout both shows. In fact, LOK Season 2, which I have already explained was one of the bad ones, had probably the most world-building out of either show, as it explained the mechanics behind many concepts behind the show, and even answered a few questions that we hadn't thought to ask, while expanding the mythos in a completely unique direction with the introduction of two rather... important... characters.
I may be wrong, of course, but I honestly get the impression from the way you phrased that response that you view world-building as the primary 'interesting' point in a story, with the characters and plot as secondary elements. I'm not actually sure the Avatar series is for you if that is the case, as while it does have worldbuilding in spades, that is secondary to the plot, which is in turn secondary to and driven by the characters.
Speaking as a writer, those should always be the priorities, and with the exception of certain epics, (Lord Of The Rings) putting the world first generally is not a good move. Indeed, while Bionicle G1 had an absolutely fantastic sense of World-Building, as you've said, it was ultimately driven by the story first, world second, and characters third.
Similarly, while G2 seems to be putting characters before world this time, I think the plot is still the dominant factor - so long as that's good, then G2 will do fine. While perhaps simple at the moment, I have seen nothing to suggest how well that aspect will fare in the long run, good or bad. I think that more than anything is what is compelling me to keep an eye on it.
In short: While you have a right to your opinions, I honestly don't think you'll find much to like in media if you really believe the Worldbuilding to be the primary point of interest. G2 is still based most heavily in story, which strikes me as promising.
And just for the record, I hated 2006 (though my opinion has softened considerably over time) and love 2007 - and not just for Matoro's sacrifice, though that certainly contributed a bit.