A big Sam would have him underestimating his own strength… things are so much lighter now! Who knew he’d be so strong? And Dean would have to make sure Sam knew where he was at all times, since the younger brother is nowhere near as used to watching where he walks as the older brother is. And we all know how Dean is with heights. The poor guy will not enjoy hanging out on a shoulder the way Sam does at all!
Maybe he can at least discover the joys of giant pie, if Sam can figure out how to use a credit card and buy him some.
There will definitely be some size shenanigans in the future of the series! Things would be too easy to just leave things alone, right? Those boys have to stay on their toes!