Hello Carl,
Sure!
I notice that all these labels start with 'k__Bacteria', so you could change the color legend title to 'Bacteria' and remove this prefix from the taxa themselves. You could also remove the prefixes like p__ and c__ from the taxa strings.
To make things even simpler, you could merge ASVs based on taxonomy and plot that instead, just like you suggested!
This could be done within Qiime 2 using qiime taxa collapse or within Phyloseq using tax_glom().
Merging / collapsing / conglomeratinging features by taxonomy reduces resolution and introduces classification bias! But it sure does simplify visualizations!
Colin