Here I doubt (and hope) we'll have that problem, but one thing that we can do to avoid it (if post counts stay visible) is keep it so we don't get little shields and swords and horses and rings for however many posts we have. That might make people actually think that post counts matter. Here our titles are our own and not contingent on how many posts you make.
There is always going to be a seniority in the member ranks. That is inevitable, but I don't think it is necessarily bad. Seniority is going to come about regardless because people will either post topics saying "hi, I'm new" or it will be apparent who knows who and who doesn't know anyone. Seniority could work in our favor because those who have been members can and I'm sure would, help those who are new to the site. In the Counter-Strike server I play on (called Newbie Roundup) we have plenty of newbs come on and ask for help and almost always a regular will do what he or she can to help the newb.
Those are my thoughts on the matter. If post counts and join dates are voted to be hidden so be it...