Another artist who would have been a good replacement for Berni Wrightson on SWAMP THING in 1974 would have been another artist contributing to HOUSE OF MYSTERY, by the name of William Payne.

In particular Payne's contributions to HOUSE OF MYSTERY issues 206 and 207 in Sept and Oct 1972.
Here are both complete stories for your reading pleasure:

"Last Ritual, Last Rites", 10 pages, HOUSE OF MYSTERY 207, Oct 1972.
http://www.12comic.com/issue.jsp?id=190227114008eti9&cu=114

"Sentimental Journey", 6 pages, HOUSE OF MYSTERY 206, Sept 1972
http://www.12comic.com/issue.jsp?id=190227114008xd2e&cu=115


Payne has a very unusual page layout, panels that blend together with a surreal and otherworldly effect that lends itself well to stories of the supernatural. With heavy black areas and a lot of fine linework and detail.

He only did about 30 stories, from 1972 up until about 1980, mostly 7 pages or less per issue, for DC mystery and war anthology books. Too bad, he could have contributed enormously to any regular series he might have done for a year or two, such as Phantom Stranger, Deadman, the Demon, Spectre, or possibly even Batman.