There are some things in comics one just doesn't mess with. Fans of both sides of comic page were practically seeing red over the Captain America of Heroes Reborn having a S.H.I.E.L.D. logo on his mask rather than an "A". When Marvel removed control of the book from creator Rob Liefeld, changing it back was one of the first orders of business. And, like Cap's "A", Vision's word-balloons may not have been the rectangloid ones from his first appearance, but it's now tradition, it's the classic look and feel [which is what the Avengers reboot was supposed to have been all about], it's the way it should be.
So, what's a Vision fan to do about it?! What's always been done when there's something wrong with our beloved past-time: write and @itch about it! Aggressively! Although there are no monetary dues for VFSYWB membership [who could afford it with the price of comics these days... and if you can, send some my way!], it is required that members send an e-mail to Marvel on the issue, advocating that the word-balloons be returned to their classic design, Cc-ing or Bcc-ing the letter to VFSYWB here. Members may write letter of their own or use a form letter from VFSYWB, either cut-&-pasting, linking, or attaching the chosen letter; the VFSYWB and balloons graphic at the top of this page may also be used. Although only the one e-mail is required, members are "strongly encouraged" to do so more often; once a month would seem appropriate, though every 2 weeks or even every week is quite alright.
Hopefully with the deluge of mail decrying their use, Marvel and the Avengers team will soon concede that the new balloons are not an improvement or even equal to the previous, even that they contradict the supernatural quality which Vision creator Roy Thomas had deigned to give the character. Again, with Avengers supposedly returning to it's former glory, the decision to change this quintisential part of the character described as part of the heart and soul of the Avengers is an inexplicable mystery. After all, even Rob Liefeld and John Byrne both know what Vision's word-ballons should look like!