My suggestion would be to
a. See if the claimed result is interesting. If not, reject.
b. If the claimed result is clearly interesting, be honest and say that the paper is clearly not publishable as is (and give your points 1-4, though really already 1 is sufficient), and should be revised before refereeing (this is often a box you can check if use one of the semi-automated review submission systems), but you would be willing to look at it once it is so revised.
c. Only get nervous over your own papers.