For small airlines, yes it is. I realize you are slot constrained, but more slots will open up, and you are not competing at all on many of the major routes out of your airport. Just because someone else has a filled the demand doesn't mean you should just give the route up to them. If you open another base the only hope for success, given your size, is if it is one no one else is based at, which means it will be pretty small with small demand. You might be able to base a few planes but the overhead will make it unprofitable. Far better to maximize the potential of your home base which has large demand.