I have been flip flopping back and forth between teams since I started to prepare for this event or that event. or this raid, or ships since I started. Not one of the teams was something that wasn't on my list to begin with. I think I have done an excellent job of determining which needed the most attention at the time and farming appropriately.
All that being said, I still have many abilities I need to level on many toons, but I am finally at the point where I have no teams I absolutely "need" to farm up outside of a few more characters for offense and speed mod challenges, but I am most of the way that I need to be for those as well.
Don't be afraid to switch back and forth between your different teams as things unlock and priorities shift. Just try to be strategic about when you shift, and it will all work out.