I imagine that will depend on how the current event organisers feel about this weight class, or if they can fit it in. Most of RR, RL and RC's shows are already extremely busy and fitting in fights for another weight class in their standard 2-hour show slots could be difficult. I guess it would also depend on how this new weight class is to be viewed. For example, these machines could be fought during the breaks between shows at the major events if there is more focus on having fun with kilobots than attracting a viewing audience. These could also possibly form part of the Saturday night entertainment at two-day events especially if the smaller arena can be moved about quite easily.

Alternatively they could also work out very well as their own event, like AWS or RRC etc. If you view videos of similar-sized robots in the US, there are often large crowds in attendance so there could possibly be a good draw of audience members if this weight class had its own events, even if it is just people from the local neighbourhood or community. Having them at their own event could also ensure the machines are working to the best of their ability; for example if these were running at an RR event, a competing team could already have one or two heavyweights, two featherweights and possibly even a Battle Rat (another class that will be needing showtime at RR events) to keep running and the little kilobot may get neglected and not be in full competitive state for the kilobot battles.

So, in summary, I haven't actually given a decisive answer to your question (nor is it my decision) but hopefully it's food for thought