I know rochdale pretty well.I have never lived there but my mums side of the family are from there,got aunties,uncles and cousins living in various areas around dale and heywood (i'd count that as rochdale,but hey ho),and have visited them all my life,even been watching dale a fair few times with them.I dont think its as bad as people are making out.I think its just a sign of the times at the moment.there are pubs,clubs,shops and houses,closed down and boarded up everywhere at the moment.
If you take macc as an example,couple of rough-ish estates,but many affluent areas.still shops/pubs etc boarded up/closed down in town centre.
everywhere seems to have gone downhill,but it depends where your starting point was,and rochdale has never been described as posh!
If you want to make somewhere look bad and focus on the bad points,its easy to call it a dive,as it has many bad points,but there are some good points.
Something i believe is a problem with rochdale,is the asians and the whites have never really integrated,and with the amount of other eastern european settlers living there now,this problem will only grow.you cant have 10 different groups living in a small space,ignorant of each others lifestyle and ways.there will be various flashpoints and eventually it will explode. As someone else has said,bring in 3rd world settlers,and you'll create a 3rd world.but if these settlers are taught about the ways and lifestyles of the people already here,and vice versa,they explain their own,it can and will work,and hopefully will make a great place to live.