In my view, there was a long period in which analytical philosophy had little to say about ethics. I think their intellectual tools did not do well with it, and analytical philosophy was above all about revolutionizing the philosophical tool box. It was more or less assumed that the Truth about ethics was some form of utilitarianism (perhaps because some consequentialist calculus looked to them like a respectable tool). Kantian ethics was then interpreted as a particularly odious version of the False - "deontology" - and treated with contempt.

Marx's writings still have something to teach us about capitalism. They have little or nothing to teach us about any alternatives to it. Anyone who had read them knows that.

As with many metaphysical and religious questions, Kant thinks they lie beyond our power to answer them. If you can't stand the frustration involved in accepting this, and insist on finding some more stable position which affords you peace of mind and intellectual self-complacency, then you will find Kant's position "problematic" in the sense that you can't bring yourself to accept it. You may try to kid yourself into accepting either some naturalistic deflationary answer to the problem or some dishonest supernaturalist answer.

Kant says that we may regard ourselves as legislator of the moral law, and consider ourselves as its author, but not that we are legislators or authors of the law.

Adam Smith saw the greed of modern capitalism for what it was - a form of destructive ambition that may have favorable effects on the productive capacities of society, but which is of no direct benefit to anyone - not even to the greedy themselves, whose illusory chase after a will-o-the-wisp leaves them morally bankrupt and unhappy.

Many who are committed to reason and science have turned against religion altogether and treat it with fear and contempt.

I think Fichte did take it further than Kant by arguing that we can regard the moral law as objectively valid only by seeing it as addressed to us by another being, even though Fichte thought God could not literally be a person who could address us.