With the likes of germany, spain, italy, brazil, argentina, netherlands, and even belgium participating in the world cup, its going to be very hard to predict who will win. but i think some has greater chances of winning than others. Therefore i will be talking about each country one by one.
Uruguay - they performed very well at the last world cup. and considering the fact that the likes of cavani and suarez are really on fire now, i think they will perform well. but sincerely, they wont reach the semi final. times have changed.
sweeden - lets hope they qualify. ibrahimovic is their only threat upfront. and since he is not maradona, they will have to try again at the 2018 world cup, if they ever dream of winning one
netherland - i think the netherland of 2010 was really really better than it is now. most of their players are now old, though still very much in their prime, but lacks the quality that will see them through to the semi final.
england - england is a real joke in the international scene. they have great qualities that should see them out class any team in the world, but... i will just say they have been cursed. and for them to have any significance at the world cup, they need much more than rooney and welbeck spearheading their attack (though im a united fan). so imo they wont reach the semi final.
italy - the italians are very ambitious people. and with past records there to boost their morales, i think they should perform well. and thereby make the semi finals.
belgium - the belgians have been fantastic all through the euro qualifiers. and they also have great players with world class qualities. and they are also well motivated. and in 4 years time, i think they will be one of the world powers when talking football. but as for now, i really don`t think they can make it to the semis.
portugal - they have great qualities too. but i will write them off based on past perfomance, which i know shouldnt be a determinant, but lets take the risk.
germany - the germans are definitely a force to reckon with in football. but i think the germans of 2010 is still way better than the germans of now. but still with that, they will definitely make the semi finals. they have past records, name instilled fears, and also good morales to shoot past any opponent. but i dont see them winning the world cup.
argentina - have been dissapointing in the past recent world cups. even with messi, i dont think they will make any difference. so imo they wont reach the semis.
spain - just the mention of their name is enough to paralyze any opponent. they have great players. and are also equipped with fantastic game play. they will do very very well at the upcoming world cup. but they wont win. i think most of their stars right now are old legs, and definitely not a world cup winning material. they will reach the semis though.
france - everyone considers france as a total write off. but football isnt like that. in 2006, they were also considered a write off, and went on to reach the final. and would have even won it if not for circumstances that were against them. therefore they are worth a mention. but still, they wont reach the semis. the world cup is no child`s play.
brazil - the brazillians need to prove themselves at the worldcup. they are under pressure at home and away. their confederation cup victory really did help to pacify many critics, but that is not enough. their confed cup victory also helped boost their morales. and with the 3-0 thumping of spain, the boys will really feel that they could beat anybody. in the next four years i think brazil and belgium will be the force to reckon with in football. so with a bit of luck on their side, brazil would not only reach the semis, but also win the world cup.

feel free to share your opinions

I quite agree with you on most of your points! Brazil will win we can guess! Being the host has always help them in their world cup history.one thing we cant over-look is that modern football is tougher than it use to be so lets keep our fingers crossed cos we're about to witness the most exciting fifa world cup final yet!