There are way to many myths going on about reanimator. It does not let people rally, it does not run off and attack things you aren’t targeting. It literally does not hurt anything (except maybe your fine sensibility at witnessing its horrificness).
There are plenty of minor traits in plenty of classes that are build specific. Look at the elementalists. The first 4 Adept minor traits only proc if you are in their given attunement. They help a little if you aren’t focusing on them, they can help more if you do focus on them.
There is no reason that the adept minor trait of the Death Magic line shouldn’t be inherently linked to, you know, Death Magic (you know, summoning minions).
The ele traits are not build specific. Every ele uses all of the elements, doesn’t matter if they are burst spec, condition spec or what ever but those traits are always (somewhat) usefull.
Reanimator on the other hand does virtually nothing for a conditionmancer, nothing for a powermancer, nothing for any build that doesn’t focus on minions. And even then I wonder if it’s usefull.
I use staff a lot in dungeons and big events, but to get greater marks I am forced to have a useless minion. Look at the other traitlines. Their minor traits aren’t all that great, but they are usefull for pretty much every build. And with no side-effects such as getting aggro from mobs.
If the minors in death magic gave some sort of bonus to your minions, sure. Just as long it doesn’t actually force you to use one just because you want Staff to be a viable choice.