Regicide might have been a good idea on paper, but in execution it has one major flaw: The lack of initiative to be king. As the king you are a bigger target and receive less points than if you were to go for only regicides. The only advantage of being king are the bonus experience (I do not believe they add towards your score) and kingtaculars. Being the king in regicide needs to have more reasons actually try to hold the crown.
Some possible suggestions I have are:
Increase the shield strength of kingtaculars.
Remove kingtaculars and add ‘royal ordnance’ of weapons and/or power-ups.
Increase the number of points received for each kill while king.
Maybe slightly buff the king’s shields (6 shot kill?), king movement speed (1.1x), or damage done by the king (1.1x damage).[/li]
Only one of these changes should be made
Feel free to criticize my suggestions (since that’s all they are).