Dragon teams are all the rage right now on consoles, and of course, The Dragon Soul is right at the heart of that rage. I would estimate that about 40-50% of the teams I encounter in PvP have at least one TDS. I like him, too, don't get me wrong, but his legendary trait DEFINITELY needs to be changed.
Why? The problem with any trait that triggers on death is that its usefulness becomes incredibly weighted in favor of the computer opponent just due to the sheer number of times each player's troops die. Theoretically, sure, if both my opponent and I are using TDS, we could both benefit from a 25% chance of having another TDS spawn. The reality, though, is that most players win more than 90% of their battles, and most battles are won without losing a single troop. I win over 98% of my invades, so while practically every battle against TDS affords the opponent a chance to respawn, in only about 3 or 4% of my games do I have a similar opportunity. I can honestly say out of the 200-300 games I'm played with TDS, I don't recall him respawning for me once (it's certainly possible he has, though). Just in the last hour of PvP, however, I've encountered four particularly ornery opponent TDS's that respawned four or more times. Playing Whack-a-TDS is not a particularly fun game, even if you still come out victorious in the end.
I think Infernal King's legendary trait is fine, because it was unique and the first of its kind, and I always thought of him as the eternal king anyway. Aside from the obvious fact that TDS's trait is a carbon copy and thus not truly "legendary", I don't identify TDS with his current trait, and it makes an already annoying troop that much more annoying.
I am not unmindful that some traits are important for defensive purposes. But I think traits should be fair game for everybody. I sincerely hope "on death" traits are used sparingly (particularly for legendary traits), and that the much-needed replacement trait for TDS does not employ such a requirement, because it means that for the vast majority of battles, players won't have access to its use.