What compression is better to use for textures of a 2d game for pc?

The cg artist with whom I work says that dxt5 lowers the quality of the sprites too much. Bc7 maintain a good quality but is usable only with pc dx11 and furthermore he not permit to use sprite packer, worsening considerably the workflow.
I read in some posts to use textures not compressed, this means to use rgba 32 not compressed, this is ever valid? also for games with many sprites not pixel art?
What is preferable to do in these situations?

 

If your sprites are relatively low resolution, it's totally fine to use uncompressed. Honestly even if they're quite high resolution uncompressed is okay. For example Rayman Legends used uncompressed textures on all platforms. It's not a Unity game, but that's not really a factor. Plenty of 2D games also load png files or (using assets on the store) svg files directly from disk and use them as uncompressed textures in the game even on mobile!

 

Thank you, now i have no more doubt.

 

It also depend on the coloring of your assets, find source that explain the compression system and you may design around it to maintain hi quality.
http://www.fsdeveloper.com/wiki/index.php?title=DXT_compression_explained