As for the commanders, heres a few not mentioned yet
This attack, followed by Second Strike, which can do up to 70 damage for 3 or 2 with an Energy Gain are overpowering reasons to play Dialga G LV
It's the only WIND level 8 synchro that doesn't have material restrictions (although Crystal Wing is usually prioritized), so it's easy to synchronize with WW, so it's being considered for adoption there as well
If Thief of Existence is countered or otherwise leaves the stack in response to that triggered ability, the triggered ability will still resolve as normal
Oh, and it's nigh-impossible to kill for good
The triggered ability that checks to see if X is 5 or greater refers to the value of X that was chosen as the spell was cast, which may be different from the number of counters it entered with if there are replacement effects involved