Truth, I was comparing them in a vacuum and I kinda slipped back to comparing them on a one for one basis when your point was that Tough can apply multiple times per round. If your opponent is making 4 effect die rolls per round, then the Tough -2 trait will be coming in handy just as often on a per round basis as the Melee +1 trait and be having a greater impact on the game. Preferably though, your opponent isn't getting in more than a couple of attacks on your mage each round. If he is, then you're probably in trouble no matter which trait you have.
We could then jump into talking about stacking armor diminishing Melee +1, as well as counters to your opponent stacking armor, and how this would cause issues for both versions of the mage. We could also talk about the Synergy with the Colossus Belt (and perhaps some to be announced spells) and how those affect both versions of the mage. We could go into quite a bit of conjecture (conjecture for me at least since I haven't tested it, lol).
I wouldn't be surprised if the Tough trait does end up proving to be better, especially given your testimony of having actually used it (which I kinda forgot about people being play testers on here and was just gleefully indulging in playing with it in my mind). However, I haven't been shown any actual reason yet why they aren't both decent options. I am a fairly aggressive player myself, and the extra attack dice look very enticing to me (if the Warlord had the cards to back him up). I probably would gravitate to the Dwarf in the end because, everything else being equal I do think the Runesmithing is better than Veterans, and I really like Dwarves more than Orcs, lol. Besides those two things though, I think the extra attack dice on the Orc are still solid bonuses from my perspective.