They have the assets, yes, but the can't chunk out $17billion in cash, plus pay face value for preferred shares, plus pay creditors, etc. They're not going to give WMI in excess of $24billion. Jamie Dimon doesn't have that in his wallet.
Stock swap? Maybe. I don't see an "all cash" settlement. JPM needs their cash reserves just like everyone else. Let's examine their most recent filing and see how much cash they have sitting around and how much their reserve requirement is. Their cash reserves won't be 5x their minimum bankroll requirement... I guarantee you.