Thing about threat is it only mattered when people were threat capped which didn't happen all that much until fury actually became good, which as far as I remember was around AQ40 too or maybe some point during BWL once people started getting geared there but at that point everything was on farm so it kinda didn't matter. So Shield Slam being good for threat was kinda pointless because threat wasn't really a concern other than Vael, which was its own shit anyway.
Pretty sure that's something like what I was using back then before AQ:
Warrior Talents - Legacy WoW - Addons and Guides for Vanilla, TBC and WoTLK
And it wasn't really a big deal, tanking was pretty much never the bottleneck for progression, retarded hunter tranq shot rotations and people exploding the raid with some random shit debuff or idiots forgetting their onyxia cloak before the 25dragon fights in BWL were. We still cleared BWL server first and as far as I remember from back then, we were top 15 world horde side or some shit like that, with most people running pvp specs because we'd often start the raid night by killing the main alliance guilds in blackrock while waiting for the same always late fucks.