In this passage there are two instances of textual variation between the adjective great and its comparative form greater. In verse 4, Oliver Cowdery initially wrote “it would be the means of greater loss” in 𝓞; then virtually immediately he corrected this clause by adding the indefinite article a (thus “it would be the means of a greater loss”). The a was inserted inline without any change in the level of ink flow. The initial text here in 𝓞 may have been influenced by the occurrence of “a greater tendency” in the following clause (near the beginning of verse 5). In any event, this error in verse 4 was immediately caught: Oliver erased the a and the comparative -er, giving “it would be the means of great loss”. The original text undoubtedly read this way.
When he copied from 𝓞 into 𝓟, Oliver Cowdery correctly wrote “great loss” in verse 4 and “a greater tendency” in verse 5. But the 1830 compositor was influenced by the occurrence of “great loss” in verse 4 and ended up setting “a great tendency” in verse 5 rather than the correct “a greater tendency”. The 1908 RLDS edition restored the original greater to the RLDS text, but the LDS text has maintained “a great tendency”. The critical text will restore the original “a greater tendency” in verse 5, the reading of both 𝓞 and 𝓟. The use of the comparative greater is supported by the parallel occurrence of the comparative more powerful in the immediately following yea-clause:
Summary: Restore in Alma 31:5 the original comparative form in “a greater tendency”; also maintain in Alma 31:4 the corrected reading in 𝓞, the noncomparative great in “it would be the means of great loss on the part of the Nephites”.