I suspect that the issue here is not that there is anything 'bad' about these ideas, just that they are naive and simplistic.
/bring our troops home from Afghanistan/
yes - and i bet all the parties would like to wave that particular magic wand but it probably has repercussions on other aspects of foreign policy and allied co-operation in NATO etc
/Put a stop to immigration/
what? even when we need skills the current workforce can't provide? I think most people would pragmatically settle for more control rather than a blanket ban.
/Raise the weekly pension to £150, the £18 billion Lab-Lib-Con give China and India to 'adapt' to non-existent Climate Change should go to our pensioners/
Two points here. First, the pension should be raised, current rates are a disgrace for such a large economy as ours. Second, the government waste £18 billion in all sorts of places; I suspect the deal with India/China is a lot more complex than us packing a ginormous suitcase with cash and handing it over.
There will be other dependecies but the subtleties of such global deals may have eluded the lads at Skinhead HQ.