A more focused beam is more efficient, but as the energy output gets more poweful, it became harder to focus. See the nukes, where reducing the yield from 20 kt to 1 was harder than making a H-bomb
Only 2 more things would make this more epic 1) The Stoner Sunshine theme and 2) Shin Getter using the Shin Shine Spark^^ Yeah I know Shin Dragon has the Shine Spark and yeah Shin Getter never used it in the series but would still be awesome :)
One could make the argument that a more focused beam allows for more destruction on the opponent, rather than have it be spread on the opponent and the environment around him.
the 3rd abyss watcher This is Ryoma as he was in Getter Robo Armageddon which has his personality more in line with the manga in terms of psychoticness.