I need to brighten all the poages in a scanned pdf. Is that functionality gone from DC?

I agree with Karl. Brightness was never the option in past, neither an inbuilt image editor.

These option for Touchup Text Tool under Tools>Advanced Editing were from older version of Acrobat 9 and 10, and now the Edit tool has been completely re-written.
You can find more Edit Object in the Print Production Tools. Check this article, it may help a bit more: https://helpx.adobe.com/acrobat/how-to/edit-text-images-pdf-files.html
https://helpx.adobe.com/acrobat/using/print-production-tools-overview-acrobat.html#print_production_tools 

Thanks,

Akanchha

All the edit tools are collected under "Edit PDF" - however, there was never an image editor built into Acrobat. You always had to use an external TouchUp editor. This functionality is still in DC: Just select to edit your PDF, then right-click on the image in question, and if you configured Photoshop as your default image editor in Acrobat's preferences ("Content Editing"), you should see Photoshop under "Edit using...".