The first Transformers was enjoyable because the good stuff far outweighed the bad. Unfortunately that balance shifted in the sequels (to varying degrees) to the point when I don't enjoy them at all.
Having only seen the first two monsterverse movies I can't comment on GvK, but with Godzilla I thought it was a similar case of too much bad for too little good, except replace bad with simply dull. Skull Island was a lot of fun though.