Apparently that was due to fans complaining. Toriyama had intended for Gohan to be the main protagonist of the DBZ section of the manga/anime. Apparently he was even supposed to be the first to go Super Saiyan, but he was pressured into making Goku the hero because that's what fans wanted.
Not sure how true that is, but that's what I've heard before. Sucks too, Gohan was so cool until after the Cell saga. =<
Oh how I love this guy, it feels like I grew up with him. Moved around heaps and every city/country we settled in I've marked with which episode of DBZ they were up to. Gohan and Bulma's hairstyles were the prevalent factors of change. Back then DVDs were only surfacing as the general media, the franchise itself was just breaking into rotation and cable wasn't as widespread, so it took a good while and a lot of revisiting to actually see the DBZ storyline from start to finish. In that sense, I've gone from age to age along with him, have celebrated his victories, cringed and laughed at his domestic turning points (study vs training; Chi-Chi's lectures), felt his sorrow and anger, and bit down those nails during his epic milestone moments. I love how he literally grew up before my eyes, from boy- to manhood, throughout the entire Z-series. It layered so many dimensions onto his character development and opened up my overall perception of the concept to new levels. HOWEVER, it is so sad how they emasculated him in the latter seasons and ESPECIAL-FRICKEN-LEE in GT!!!
Tl;dr - your epic piece of epicness filled me with so many damn feels. YOU ARE VICTORY. ALL OF IT.