I take vetoes and trading pretty seriously. Inconsistent policy seems to be the main cause of arguments in all worlds.
I'll use an example from one of my worlds to make a point. An owner apparently needed to create some cap space to make a move. So he traded one of those low DUR/STM pitchers, the 40 inning-types, making 2m for a training camp pitcher. The BL pitcher, no matter how limited he is in the regular season, is a nice playoff addition when you can afford a shorter staff. Well, as it turned out, the team that got the BL pitcher made the playoffs and, of course, had the pitcher on his playoff roster. The owner who got the TC pitcher missed the playoffs. While I'm pretty sure I know the intent of the deal, the reality of the deal is completely different. A non-playoff team traded a BL-quality pitcher to a playoff team for nothing. Is that good for a world?
And that's why I don't want 32 guys attempting to figure out if a deal is "good". Have trade rules, abide by them.