Introduced by Lord Mandelson in a late change to the reorganisation of further education funding, it was immediately criticised by the union representing funding body staff as "ill thought-out and rushed".
Now Conservatives are threatening to abolish RDAs altogether, with skills planning taking place through negotiations between a central funding body and providers drawing up local, strategic plans to meet employers' needs, simplifying the process by cutting out some middlemen.
The Liberal Democrats have also put RDAs on notice, saying they should focus on economic development only and that they will be scrapped if they do not have strong local support, with their functions taken over by councils.
The party's figures assume that it will save at least pound;600 million of the pound;2.14 billion budget controlled by the regions.
RDAs are barred from publicly defending themselves during the election period under civil service purdah rules, but FE Focus understands that they fear there will be no one who will take on a forward planning role who understands the needs of different economies in each part of England.
Members of RDAs have suggested that employers themselves have not got a good track record in taking the longer view. One said: "In my experience, businesses tend to take a very short-term view of their short-term business needs. When they do take a wider view, it is of generalised skills rather than specific vocational skills."
Bodies such as the UK Commission for Employment and Skills have also expressed concerns that employers are not all well-equipped to make use of high-level skills and may need outside help.
But it is conceded that the performance of different RDAs is variable: one solution might be the system of testing local support proposed by Liberal Democrats - but that risks creating a patchwork system with varying approaches across the country.