Regarding getting your builds noticed, I think you are doing a great job by showcasing your builds here and it sounds like you use Twitter as well. Other people also have blogs, and you may want to consider branching out as well to reach more people. But specifically regarding Maxis, a couple of points to consider:
Maxis may not favorite things for the same reason another player favorites things. They have a product to support/promote. Maybe they feel that spreading out their recognition to many people will encourage more people to try building, or that if they favorite a wide variety of items, they are more likely to end up hitting on all tastes and increase players' use of the gallery. Maybe they saw a tweet from someone who just built and uploaded something for the first time ever, and they favorite it to encourage them to keep doing it. They may see a really great upload from someone whose work they've favorited before and decide not to favorite it if they are concerned that consistently favoriting the work of a few will discourage others from trying. Maybe they don't favorite everything they love because they're trying to find a balance between giving as much recognition as possible while being considerate of the players that have complained they want to stop receiving so many favorites notifications from Maxis.
Even if Maxis were favoriting strictly on the basis of which items are the "best", you have to remember 1. taste is subjective and 2. Maxis is likely hampered by the same gallery issues the rest of us are, like too many items to search through and inconsistent use of hashtags, not to mention even getting the gallery search features to work reliably. The odds that they'll notice every build that deserves to be seen are very slim. In fact, I'd bet there are a lot of very talented builders out there that will never have anything favorited by Maxis, and that's not because it wasn't good enough or Maxis wasn't trying . They just won't be able to find and favorite every good upload, the same way you wouldn't expect a normal player to manage to favorite every good thing that ever hit the gallery.
My point isn't to lecture you, so I apologize for my long-windedness :) I just wanted to point out that there are plenty of reasons for items to not be favorited that have nothing to do with the quality of your builds and encourage you to care less about what Maxis favorites or doesn't. Your builds are lovely. If you love building, keep doing it - that's all that really matters anyway.
