So... I've never really got into Dragonball... Z or otherwise... I know I know, shame on me... But, while Goku seems strong and does seem to get overloaded with different powers that cover many bases, to begin with his powers just seem to help him attack and defend in a fight. He can he is super strong so he can give and take super hard punches. He can move super fast so they can box and block in super-speed. And he can fire a big laser. So he has a lot of destructive potential, but he is also in a setting and up against other beings that can withstand him, so the conflict and tension can remain. Later on, I understand that things escalate to insane levels of power and destruction, plus he like dies a couple of times and comes back to life, and he learns a bunch more abilities that cover even more ground... It sounds like he's stronger than superman and without the weakness of kryptonite (and I already find superman pretty boring...), so for me things start to break down from a perspective of writers using Goku as inspiration. It seems that a story involving Goku can only really be about who wins in a fight between him and another DBZ character, because he can basically destroy every other obstacle in the universe, go anywhere he wants and make or take anything he wants. The only other thing to write about would be romance and interpersonal drama - things that cannot be solved through might alone... but then there are other series that explore those kinds of concepts way better.
Personally, when I think of DBZ and its head-to-head fight plot-lines, I'm pushed in the direction of other martial arts series like Gamaran, Kengan Ashura, Baki, The Breaker etc. These are somewhat more grounded/physics-bound and give more space for the focusing in on the techniques they are using as they happen, as opposed to the effect afterwards. The story-lines will focus on the motivations and growth of the characters involved of course, and who has the nerve, will, creativity and ability to win, but the moment to moment action is generally more engaging to me, in these kinds of stories, when it can be zoomed in on rather than zoomed out from.
Talking about overloading Goku with powers actually jogged something for me. In a recent Guild Wars 2 development livestream they outlined their principals when designing and balancing classes, and a couple of them are particularly pertinent I think:
"The following are a few key ideas that we consider when balancing skills and traits. This list isn't intended to be absolute in all cases, but there should be a strong reason when a skill breaks one of these rules.
Purity of Purpose
Purity of purpose is the idea that a skill (or trait, or weapon, etc.) should have a well-defined identity. In other words, skills should not do too many different things at once. Some common skill identities include damage, defense, support, control, and mobility.
Holes in Roles
This is an idea similar to purity of purpose, but applied to builds or professions. As we touched on when discussing identity, we want every profession to have distinct strengths and weaknesses. Professions should have things that they excel at, things that they are less effective at than other professions, and some things that they simply cannot do. If one profession does everything and has no holes, there's no reason for players to play anything else."