I think icons at the bottom could work better and it's good to encourage conversation over presentation, but it's strange that they appear part of the text area. What happens when there's a scroll bar? I think it needs a gray divider (like VisualEditor in a page) or background (like Gmail, the wiki editor toolbar, etc.).
Is the rightmost <> icon the one-way "Switch to source editiing" as in VE?
Pau, is the change to heavy gray "Reply to Ludmilla" placeholder text in your design intentional? The current lighter italic "Reply to "content of post"" looks better. What's the rationale for changing the placeholder text from the message content to the person to whom you're replying?