It has been suggested that we have a canonical question on what machine can be used to develop with e.g.
The first one is simply
I want to buy a MacBook to develop iOS apps. What are the minimum requirements?
I would suggest that this is difficult to do - I am raising issues here so the question looks very slanted - so I think the best way to show agreement or not is using metas different meaning of down votes - a dozen vote does not mean the question is bad just that you disagree with it. (Or someone can see how to edit this into a neutral question)
The issue that I would raise is how can we keep this up to date. This question was asked in Sept 2010. The comments and answers imply that the base model with 4GB RAM would be sufficient. However nowadays I would suggest that Xcode takes more memory and you need 8GB.
I also think this is not objective as development covers a lot of things. Simple web front end development in HTML and CSS needs no more than add ins to a browser whilst writing large C/C++/Objective C/Java programs require much CPU and memory for compilation.
What possibly could be done as occurs in the uprooted answers is to emphasis which parts of a Mac are worth upgrading e.g. RAM to a certain level, then SSD rather than Hard disk and then also CPU e.g. this