At the moment I'm just getting a few ideas out of my head, and into working prototypes. One of these is Pocket Battlers, in which you control a small 'Battler' (as a sub-avatar?) that can move around and launch various attacks. A major feature is that these Battlers can be very different, for example in the first generation with be a tank, a pirate ship and a faery; all with appropriate movement and unique attacks.
The second major feature is the power bar, through which attacks are activated. Power gradually accumulates over time, and each attack requires a certain amount of power before it can be used. When an attack is used then a portion of the power is used up. You can see it in action at the end of the video below (there's no sound so don't go fiddling with your volume control).
They still need a bit of dressing up, but after a few small tweaks they'll be at the stage where they can be fought against each other (I just need to add in area-effect damage).
Credits: The particle systems used for the faery are based on free examples available at 'The Particle Lab' in SL, and the faery's wings are by Jane Mc Carthy.