He has fought at FW already.. His only loss was also at 145. Dom openly admits to being in the high 160s out of camp, and has gained mass since he last fought at FW. So to answer your question, it would appear that he would do well at 145 currently..
Dom vs Aldo, Edgar, Pettis, Mendes, Yair, Holloway, Cub, etc.. Are all possible fights if he went to 145. Dom has also stated recently that if Conor won the 155 belt, he would want to fight Conor at 155 for the belt. At 155, Dom vs Conor, Nate, Ferguson and Barboza would be interesting, especially being the actual smaller man in those fights.
Off topic.. I think Cody, TJ, Almaeida, and Sterling do well at FW too, and see at least two of those four, going up to 145 before end of 2018.