I would say not to wait a year since you never know where prices are going to be in a year. If you're going purely for investment potential I would say buy the best Hulk 181 you can afford to sit on for a couple years, because you know eventually Disney will bring Wolverine into the MCU, but It may be a couple years until that happens. Once they do bring him in though I would imagine that will make that book appreciate quite well. If you're looking for something a little more secure though maybe think about New Mutants #98 since Disney just confirmed their Deadpool adaptation will be R rated, which could mean good news for that book. Ultimately though buy what would make you happiest.