Well he is right, 1. bm is one of the few classes where arcano is mediocre.
It is only middle of the pack when at the same ilvl.
And gets beaten by cof/cradle/medallion/bti/focci (and more..) even when these trinkets are 10-20 ilvls lower than the arcano.
2. Onto engine:
not bis ; loses out to cradle + other statsticks and medallion (naturally also a bti if you can get it that high).
955! engine <<<< 950 medallion and 930!!!!!!! cradle (naturally other haste and mastery statstics will then also beat out a engine rather easily...)
http://effin.highfiveguild.com/sims/..._trinkets.html
@BM, 56 traits, Talents (2202012), 915/945 gear, 2pc/4pc tier
The reason you see people using/ ranking high with the "wrong" trinkets --> people will use the best of what they can get/ have. In the end you use what the titanforge lottery grants you and not what the bis lists can tell you.
Only much later in the tier, towards the end of the patch, will you see the rankings get close to displaying the actual bis trinkets for each fight.