It's too hard to find attachments. It's routinely takes several minutes for me to figure out how to get to them in a long thread. Ideally, I could just click the paperclip or see a separate pane at the bottom.

I use Exchange account and folders.
I see my badge count is equals of inbox folder, but not for all folders.

This used to be the default behavior, but changed in the latest update to Airmail 2.0 - label colors now only highlight the top right corner of the message which for me makes them much harder to see.

I used this feature extensively to visually distinguish messages - I would love if this came back.

If someone sends you an email with say, 10 questions, when you reply using Airmail, you can't say, "See my answers in red below," and then answer each question, because nothing that is shown from the original email is editable! Not sure why this is, but it would make me a hundred million times more productive when using AIrmail.

You really need to make the toolbar better. I like BIG ICONS, I like to
be able to SPREAD THEM APART so I don't accidentally hit the wrong one because I go through a lot of email each day, so I like the icons to be
easily identified as in COLORED ICONS (see the POSTBOX app). Please change this!

Apps like iA writer and Markdown have a Focus Mode that only highlight the sentence you're currently typing and fade out the rest. That would be an awesome feature for composing emails:
Example: http://images.computerwoche.de/images/computerwoche/bdb/1842754/890.jpg