A custom indexer for ke_search would be very nice.
An indexer that works for all mask elements without or with little effort for the integrator.
Actually, that wouldn't require an own indexer, but a hook, as described for DCE on
Then the hook like:
to render the mask item and return it instead of bodytext.
Also see (custom indexer) https://github.com/BenjaminBeck/bdm_kesearchindexer_flux/tree/master/Classes/Helper
Of course, they could be passed through their Frontend templates in the "Content" dir.
But a faster solution would be to create a third template directory "Search", alongside "Backend" and "Content". There, simplified versions of each CE could be stored that just contain the data we really want to index.