The offer sounds consistent with the Jays stated intention to try to sign Wells before January 1, or else try to trade him afterwards.
Clearly this offer 'shows' they're serious (mostly it's just using the $ they were targeting for Lilly/Meche), and for public consumption it looks good in terms of showing they made a solid attempt to keep him around. Wells is a solid player, but I agree with weir, he's not worth more than $18M/year, and the Jays have never even been in a September playoff race in all the years he's been here. The Jays don't really improve on any of their recent teams by signing him. The fact Wells isn't jumping at so much money pretty much just suggests what most people assume, i.e. he doesn't really care one way or another if he's back here.
I think this offer is one the Jays had to make in terms of covering themselves PR-wise, but I don't think it'll be so bad off if Wells turns them down and then they can pour all that money around different parts of the team that need work in coming years (e.g. middle relief, SS, C, power OF, SP depth..) I doubt they can get "fair" value in return for him in a trade, but if they can get something coming close then that would be a very good start too.
You've got a diamond, You've got nine men
You've got a hat and a bat, And that's not all..