To be honest in my opinion the rules of the game have changed due to the job situation.
In the past it may have been the accepted route that you'd get a rotational job, work up to senior level and specialise but now rotational jobs are gold dust so people are specialising straight out of university. When I say specialising I simply mean going straight to work in an area (private/sport/whatever) without always having done rotations.
Some will say that it makes you a better all round physio if you've done rotations due to the transferrable skills but if you absolutely know where you want to work then theres no reason you cant go right ahead and do it. Obviously nothings changed in terms of the best jobs going to the most experienced people but you have to start somewhere and these days it's unlikely you'll leave uni and go straight into a rotational post.
With NHS jobs being so competitive, new grads need to leave uni with the boxing gloves on as there will be some far more experienced people applying for band 5 jobs...