@Bronze Bacon You shouldn't, its too expensive and you can save 2000 gold for other brawlers. I think it just requires patience, as the longer you don't get a star power, the increased chance of getting one.
A quick question: are there actually any creators or Supercell employees here on the wiki?
Also, Star Powers are supposed to be late-game. I just finished pushing all my brawlers to 500 today and most are power 5, 6 or 7. I have 5 brawlers maxed and 2 at level 9. So yeah, unless you're high in trophies (10K+) I wouldn't worry about star powers.
Especially if you don't have all the non-Legendary brawlers yet.