Cuban's face after his Mavs blow a 27 lead.
(Talk about a picture saying a thousand words)

Caption contest?
“Oh, man. Really wish I didn’t trade for Kyrie…” 
"I can't wait to sign and trade this guy for Ayton"
I don’t think the Suns would make that trade. It would ruin them defensively. Phoenix has the best defense in the western conference. Will be really interesting to see what Cuban offers Kyrie over the summer.
They'd be hard capped which given what Durant and Booker make, make it very difficult for them to acquire anyone that is sign and traded. That said, if the numbers worked, I do think something like Ayton, Paul, Shamet for Irving, Kleber, and Bullock (plus a couple of draft picks whenever Dallas can trade them) is a reasonable trade for both teams.
Ayton + Shamet works for the salaries. They'd have no problem fitting under the hard cap if they either traded or stretched Paul. CP3 only has $15.8 million guaranteed next year, and is fully unguaranteed the following year, so stretching him would take his cap hit from $30.8 million to $3.16 million each year for 5 years. This would leave them the cap space to resign Landale and Craig and add someone with the MLE, and maybe even the BAE, to fill out the roster.
I don't know that Ayton and Shamet works for the Mavs, but cap-wise, Kyrie, KD, and Booker can team up in Phoenix and have a few other players on the roster.