SevenShackles
Missa pro defunctis
in the fights you posted i see no problem they switch would change things of course but the good guys would win.
in a more long term look, witch enemies being switched out and having to interact and how things would change by their presence.
i dont see thor doing for metropolis what superman those. superman could handle a good portion of Thors foes and it would be rather interesting given his magical weakness. Thor himself can do the same but enemies like DD and such that put a big dent in superman he would have a hard time with.[if not need help] they both seem to be just dropped into hostile waters here inheriting each others responsibilities.
i think thor might do better than Superman. Thor can do so much more and supergirl can fill in the role of the DC Universes 'Super' person. he could fill in the missing spot in the DC Trinity if not just letting it fall upon captain marvel.
Superman.. eh. between loki and Dr.Doom with their magic. Mephisto, great beasts. given his 'save the world' attitude he would clash with many enemies with the team and alot more dangerous ones on his ow during a patrol. hell just fly over doom-country and he will have a serious problem on his hands. and if galactus ever manages to swing his way into being a threat to earth or anything near superman with his need to... ya know.. save all life. he will clash with surfer, which he could win but then Big G himself.....eh. his own personality and morality that might serve some of the heroes in the marvel U to see and be inspired by will lead him into alot of trouble. soo he gets the sh*t end of the stick.
hell whoever remembers Hyperion would probly just think hes him. "oh your that guy!"
while Thor does what he has to do, with threats as they come. swings his big hammer. yells 'I SAY THEE NAY!!' and hits the big bad of the week.
loki vs superman? cool. thor vs Luthor? in the suit is like Thor VS Ironman for me =/ so that rivalry angel is dead. the switching roles was a cool idea tho.