With the size of some current engines (trent's for example) there are huge issues with ground clearance.
I agree that maintenance is an issue, but it is not a be all and end all problem.
How about engines mounted in the rear of the fueselage, behind the pressure bulkhead.
Aerodynamicists have huge problems with podded engines, specifically in the 737 with the first CFM engines, the flow interaction between the engines and body caused all sorts of issues and took months to solve satisfactorily.
With modern materials and techniques, I don't feel that swing wing a/c are that much of an issue. How much extra weight and complexity goes into a wing for all the high lift devices, engine bits and bobs, fuel tanks etc etc.. That is a seiously compromised design. Airbus are doing O.K in this field, just have a look at the flaps on an A320 compared to a 73. Far less complex, but still pretty effective.
With a simple pivot on the top of the body and engines in the rear and the whole structure comprised of different composites, the a/c could be light years ahead of current macines in terms of weight and performance in both high speed and low speed regimes.
I feel we as pilots should start to think 'outside of the box' in regard to aircraft design. When the potental benefits of new ideas come to light, then airlines will be clamouring for them, just look what happened when jets came along. I feel its about time we took another quantum leap.