After considering my houserule on limited cantrips and thinking about the Wild Magic chart I would like to try a few more changes.
First as cantrips are limited I would like casters be be able to push that limit. To cast when they feel like they can’t cast any more, this could extend beyond cantrips to other spells as well. What happens when you try to push your limits, to cast when you have no energy or strength left…
Second idea is to be able to cast cantrips with higher level spell slots. This might not make sense for all cantrips, for example damage cantrips already scale with your level, but what about non attack cantrips. Can you cast them at a higher level for a bigger affect? Why not try?