I think nobody has really understood your question yet, so I'll try to answer it. I think those level defining elements you call them are fine in the game. Of course there are a lot that we have seen somewhere before, but this is partly due to the fact that it probably is difficult to have really new ideas in this genre and partly because this game also plays with nostalgia. There are still quite a number of new elements though and certain levels are definitely memorable thanks to those. Also, the known ones are not simple rehashes but usually clever mixups that make them feel fresh as well.
The overworld is a million times better than the one of the DS game, but I'm still a bit unsure what I should think about it. For me it is more or less on par with the one of SMB3, but still ways behind SMW's. It is good to have enemies on the overworld map and it is designed nicely, but all these secret paths and the fact that it was one continuous world in SMW make this map much better imo.
Secret level exits are existing, but the focus is more on the Star Coins which is fine, but not as good as looking for secret exits I think. The problem with the secret exits is mainly that they usually only lead you to either a toad house or a warp cannon which is both quite worthless if you have already played through the main without secret paths and are looking for them afterwards.
But I can tell you that the game is really really amazing and really in the same league as SMB3 and SMW. I'd personally place it in front of SMB 3 but behind SMW, but this is only a matter of personal tastes I think.
I hope that helps you!