Johan is obviously more valuable, but the other side of the deal isn't that bad. I own Matthews in one of my leagues, and have been extremely pleased with his production thus far. This week he's slumping badly, but I have a thing for players that give me good numbers in all categories. He's kind of like what Johnny Damon is supposed to be. Putz is a tier one closer now, so I'd say if the team needed another outfielder and a closer, and had enough starters, it was a good deal for him.
There's definately no reason to veto a trade such as this. I agree with previous posters that some managers have a misconception of what the veto is for. The value of every trade is ALWAYS subject to your personal perception of it. I mean, there are trades which the concensus thinks are unfair, but it's still an opinion. It gets obvious if one team is practically giving away their players in bad trades consistantly. There's a grey line that you have to watch, but something like this is pretty fair.