Envelope Development

For my envelope I'm trying to design it in the same colours and typefaces to have consistency, and also because it will create more of an impact when the recipient finds it in their mail. 

At the moment, I am creating the design with a door made out of text, which says 'who knows what goes on behind closed doors', because it is using wit by linking to the fact that the sentence creates the door,  and it is still maintaining the serious tone. I have also designed the other text on the envelope to be quite clever, and the use of the unfinished sentence on the closed flap of the envelope will intrigue the reader into opening the letter. 

This is what the final envelope template is looking like at the minute - I'm just worried as to whether it is either too simple, or still too much text. I don't want the envelope to detract from the speech bubble card design, I want it to complement it.