I think players who wind up overshadowed in their main role, by someone who has it as a secondary specialty, need to take some responsibility too. They need to realize that other players are going to have some ability in "their" area, especially for things like combat that most characters will participate in. So if they want, say, being the gun guy to be their role, they need to commit to that role. If you want to be the gun guy, and you are playing someone with Agility: 4 and the Firearms skill group at 4, then don't whine and pitch a fit if the face outshines you with Agility: 5, muscle toner: 2, and pistols: 5 with a specialization in semi-automatics. I don't have a lot of sympathy for someone who wants a designated role, won't make the simplest, most obvious choices to be good at that role, and then complains when someone else is "better" at it.
I'm not turning around and putting all of the blame on the overshadowed players, though. People playing characters with their A Priority in "Asskicking" still need to remember it is a group game, where everyone wants their own niche and their own time in the spotlight. Assume the gun guy at least tries, and has, say, Agility: 5, muscle toner: 2, and the Firearms skill group at 6. The close combat guy might have two cyberarms with maxed-out Strength and Agility with retractable spurs. But whoops, he has two ranged skills at 6, with specializations and reflex recorders, so despite close combat being his main thing, he is also rolling 5 more dice than the guns guy, with guns! So at that point, maybe the close combat guy needs to dial back his ranged combat a notch, so the guns guy won't be overshadowed. It all depends on how well-rounded each character is, though. If the guns guy is also a break-in guy with some face abilities, it may not be as big a deal if he is overshadowed at guns, especially if the close combat guy is a more narrowly focused combat machine. Sometimes four dice pools of 12 can be as good as one dice pool at 17.
If your group has such problems with stepping on each others toes, maybe (if it is feasible) they could do character creation together, as a group, in the future, so everyone can play what they want and have some protection for their individual roles.