Here is how I would have edited the first three paragraphs of your post on consequentialism:

The simple idea that we ought to choose actions according to their probable consequences, ever since it was formulated, has garnered a rather shocking amount of dissent. Part of this may be due to causes other than philosophical objections, and some of the objections get into the metaphysics of metaethics. But there's a fair amount of opposition on rather simple grounds: that consequentialist reasoning appears to endorse bad decisions, either in the long run or as an effect of collective action.

Consequentialism, the simple idea that we ought to select among our possible actions according to their probable consequences, has garnered a surprising amount of criticism ever since it was first proposed. As lukeprog discusses here, some of these objections are likely to be mere superficial rationalisations of intuitive moral judgements, which are easily dispensed with in the philosophical arena. Other objections may be metaphysical in nature; needless to say, most Lesswrongians would consider metaphysical objections to a metaethical principle, or indeed any metaphysical argument, to be a priori incoherent. However, a significant proportion of opponents of consequentialism argue that consequentialist reasoning appears to endorse bad decisions, in the long term and when multiple consequentialist agents produce collective action; this criticism seems more worthy of our consideration.

Every so often, you'll hear someone offer a reductio ad absurdum of the following form: "Consider dilemma X. If we were consequentialists, then we would be forced to choose Y. But in the long run (or if widely adopted) the strategy of choosing Y leads to horrible consequence Z, and so consequentialism fails on its own terms."

Occasionally, a critic will offer a reductio ad absurdum of the following form: “Consider dilemma X. Consequentialists are forced to choose strategy Y to deal with the dilemma. But in the long run or if widely adopted, strategy Y leads to horrible consequence Z, therefore consequentialism fails on its own terms.

There's something fishy about the argument when you lay it out like that: if it can be known that the strategy of choosing Y has horrible consequence Z, then why do we agree that consequentialists choose Y? In fact, there are two further unstated assumptions in every such argument I've heard, and it is those assumptions rather than consequentialism on which the absurdity really falls. But to discuss the assumptions, we need to delve into a bit of decision theory.

This argument seems suspect. If a consequentialist knows in advance that strategy Y is likely to produce horrible consequence Z, then why should we expect him to choose strategy Y? In fact such an argument relies on two unstated assumptions, and since I believe these assumptions to be invalid the argument fails to refute consequentialism. In order to discuss these assumptions, we will need to delve into a bit of decision theory.

Some of this is just my preferred way of phrasing things. In other places I do feel that it's an improvement (for example, "if it can be known" is passive voice, which is generally considered to be both dull and unclear in comparison to active voice, therefore only to be used if there's a good reason to do so).