I would suggest that you do whatever makes YOU happy no matter the cost. If the figure or area of collecting you choose is expensive then you just have to save longer in between purchases but it will make your acquisitions even more worthwhile.
If you choose a focus based on what's easy, cheap, or undone by another before you, you'll end up with an amazing focus that you don't even like and end up selling up later.
I don't focus on Fett because he's popular, I collect them because they appeal to me and make me happy. I also really love Yoda and Jawa items and pick up things in that area here and there but I have something to hunt for when the fetts run dry or my funds do
Good luck with whatever you choose to do or not do. There's nothing wrong with dabbling in a little bit of everything until the focus chooses you.
Andy A