We oughtn't forget that Cloud was in the military, for starters (I mean he at least completed enough training to become an MP), and then he got hopped up on Mako and got injected with Jenova cells, so it isn't as though he could be expected to abide by the limits of normal human strength.

From a design standpoint I just find it obnoxiously huge. The programmers must've thought so too, because he pulls it out of nowhere multiple times.