dvt, the purpose of a thread is that it changes direction slightly with each new post (provided it's still relevent). I've yet to see an irrelevent post on this thread. A new (and old) 737 driver would probably benefit from the advice and cautions of other fellow professionals.
I try to hand fly / do raw data approaches on a regular basis WHERE APPROPRIATE, plus I have the opportunity to do visual / circling approaches. I agree hand flying is important, but I think these days CRM, Teamwork, and making sound desisions are almost more important. Very few accidents are caused by pilots not having the necessary flying skills, MANY, MANY are caused by bad management, breaking rules, and get-in-itis.
I know ATC can mess you up, but if you can't manage your approach profile to such an extent that you have to side-slip then I think you're in the realms of a rushed approach. Have you ever thought what the other seat would make of you slipping on finals? I think it would make him rather uncomfortable.
You should be able to recognise early enough that you use the gear, or ask for further vectoring, or you do an early re-position. If you're high enough so sideslip, there are other, better, flight manual options available, if you're too low, then GA.
I agree that its an interesting question about whether there is any reason why you can't slip, and I would like to know the answer, but I think it's your attitude that 'only cissies don't slip' which has alarmed so many.