I won't speak on the TA vs Disembowel thing because in part it's been talked to death over the last few pages, but also because it doesn't really matter for the purposes of the 'bad' jobs in the game. Removing TA or removing Disembowel doesn't suddenly make RDM/SAM/BLM better it just makes the top tier jobs worse, which might help the second tier jobs slide into more comps for specific fights depending on what's needed but the jobs that need it the most don't see their stock rise at all.

tl;dr, if you accept an ABC tier ranking, or at least acknowledge there's a strata like it, changing A doesn't help C. It only helps B. You need to make changes to how those C tier jobs work to make them more appealing. Sure top end balance might be something people are interested in but it's pretty minor compared to how bad some of the other DPS jobs are.