Waaaaay back, those NQ prizes were the center of a lot of peoples sets. They were tedious to get because it was before auto-players ruled. They didn't break the battledome though at all because there were enough blockers to counter them (including burrow and sink).
The battledome is broken now for two main reasons:
1) The addition of anagram swords pretty made like 85% (pulling this number from my own opinions) of battledome weapons obsolete in their single release. They were too cheap, and too powerful. Hardly anything could counter them, and it broke the normal leagues of league/boost battling.
2) TNT changed the battledome and the abilities completed changed things. Some items didn't work properly, some abilities were too strong and negated weapons completely, and some abilities were equal to a sparkler + wooden shield combo.