I think Mike is the main reason why Zoey is "boring" since She only really has a major interaction with Mike and Cameron since 90% of the time Zoey was on screen she would be with one of those two characters, but i think of Mike and Cameron where not to return for a all star season and Zoey was the only one back from that group we can see her grow to be one of the better characters.
If they shown how she had a main interaction with characters like Gwen, Lindsay, Trent, Noah, Dawn, Brick, or Dakota it will turn out to be good character development for Zoey.
Also Zoey did has some great moments like her small interactions with Brick, Dakota and Dawn, how she became rivals with Scott and put him in his place after Mike was voted out, when she had to baby Cameron in TDR, or her battle with Jo in all stars.
So if Zoey does return for another season who would be the top six characters for Zoey to become friends or rivals with.
for me it is...