I lived in Malaysia for 2 years about 15 years ago and travel for business regularly now. At the time I HATED it with a passion, I would probably cope better these days.
The hot, humid all year round weather is awful, but if you are acclimatized then you might cope better. The food is great - agree with that. Agree with the other posters though, it really is BORING. Shopping malls and eating .... we really struggled for stuff to do (we like hiking for example, and the hiking in Malaysia is pretty poor except for in Sabah and it's far too hot).
In terms of conservatism, KL is fine. Some of the other provinces are not. The inter-racial stuff is not that bad to be honest. But the whole place and the people have a veneer which is hard to penetrate - they are friendly on the surface but hard to read underneath. I find that (being Australian and pretty blunt) to be depressing.
The infrastructure is much better now than it used to be, but it's still quite bad. You'd need a car, for example. Most stuff is built shiny and new but then never maintained well, so it decays and breaks down much more often than you would expect!