I wish there would be a possibility to summarize numeric dataform field content of one category into a special %%form_sum{name}%% field for the Module ListPages all selected pages of a category.

There are today such summarization fields over a "selected list of pages" like

%%children%%  Number of child pages
%%comments%%  Number of comments on page
%%revisions%%     Number of revisions to page
%%total%%     Total number of pages ignoring limit (may be higher than %%limit%%)
%%total_or_limit%%     Total number of pages in ListP

I had the idea needed in the community discussion:
http://community.wikidot.com/forum/t-776814/comments/show?from=activities#post-1968362

It is not directly the need of such a summarizatin dataform field but would be useful too.