Assembly line balancing plays a significant role in mass production systems due to production efficiency and productivity. A number of researchers have recently shown great interest in this topic, especially in the area of simple assembly line balancing problems (SALBP), and several academic papers have been published on this topic using different exact, heuristic, and metaheuristic methods. Recently, Rashid et al. (Int J Adv Manuf Technol 59:335–349, 2012) reviewed one decade (2000–2010) of published studies on assembly sequence planning and assembly line balancing optimization, those studies that applied soft computing approaches. The scope of the Rashid et al. review in the area of assembly line balancing problems was reported to be on SALBP. In this paper, we suggest that the review by Rashid et al. and the conclusion drawn regarding SALBP are inaccurate in some parts, and some revisions to Rashid et al. (Int J Adv Manuf Technol 59:335–349, 2012) are necessary. Accordingly, a revision to Rashid et al.’s review paper is proposed, and a guide to future research is presented. Moreover, to have up-to-date information, the review is extended to also include the published studies in the period of 2011–2013.