People just don't get vetoes. This might favor one team, but the 3 decent players for 2 decent players is acceptable. Vetoes are for trades like Chad Billingsley for Bobby Seay, and even that might hold some water in a roto that includes holds.
Unless you can somehow point to a comment or some other hard evidence by one of the two owners in question that a deal is being made for the sake of collusion, you don't veto a trade.
To put a little backstory on this deal, the guy trading Wright and Soriano told me he basically doesn't care and he knows it's one sided because he is in last place.
As co-commish of the league, I really believe this is veto worthy. It's a new first year owner against a vet who has a history of one sided deals such as this.
I am normally in the "If it's fair, no cheating, have to let it go" but I don't think the league should suffer because of one owner who could care less and wants to trade some of his best players go for 2 players that were on the verge of being dropped and Markakis.