The new Gmail does support other providers like Yahoo, but they wont allow conversation mode with this providers. So you see all emails one by one, kinda sucks.
Besides the bundles, done, and scheduling...why the hell did google decide to create a whole new app to confuse the masses?
Anyways, I'm going to stick with my third party email client, bluemail. It does all of the above, plus more. It only takes 2 clicks to delete email. I'm not promoting, but i'm sharing what app is better.
Blue Mail
Give them a shot, seriously you will love it. It'll be more useful for people who have email accounts with different providers and like to address emails at a later time.