What exactly is vulnerable in Active Directory? Without a clear baseline its impossible to compare x and y. This is an incredibly broad question and it's difficult to answer fully.
The pass-the-ticket/golden-ticket attacks are not themselves a vulnerability per se. The potential vulnerability is in the protection of the keys used to encrypt the tickets. Once you have the keys anything you do against the different parties is valid. At that point you're not attacking the protocol itself.
Active Directory protects these secrets in the directory database by encrypting them to a key protected by the machine. If you can get access to these secrets then you have full access to the database, which means you have access to the keys and can perform this attack. This is an infrastructure issue. If you don't do your own due-diligence protecting your critical infrastructure it's not reeeeeeally AD's fault. I say this because...
MIT supports multiple ways of storing directory data, and each one is equally at risk if you don't protect the infrastructure properly either. It supports LDAP and SQL and what not. Each of those has a database and protects their secrets fundamentally the same way. If you can attack that infrastructure you can get the keys and perform the attacks.
Now compare the protocol implementations. They're both RFC 4120 and they're both interoperable. They both support the same key types and extensions. This means any weaknesses of the protocol are applicable to both. Any pass-the-ticket/golden-ticket/etc. attack against AD is identical to MIT or Heimdal or whatever implementation is out there.
Where things differ is the support infrastructure. DC Sync for instance. Windows supports syncing directory databases between DCs using the MS-DRSR protocol, which when granted enough privileges allows you to request any secret you wish. This requires a critical privilege that isn't handed out freely and goes back to that protecting your infrastructure thing. MIT doesn't have a directory sync because it's not a directory. It's just an implementation of Kerberos. The LDAP directory you use to back MIT will however have a sync engine of some sort and will therefore have similar APIs and be equally attackable, if you get yourself into a privileged position.
that's the crux of this: if you can get into a privileged position you can attack the services. You could call it a vulnerability, but the meat of it is missing because you've magically crossed the security boundary without saying how. How you cross the security boundary is more appropriately the vulnerability.
All of that said, the reason Active Directory is the problem child here is because it's the most common and its makes it incredibly easy to automate equally good and bad behavior. It's the one everyone knows and it's had its share of bad press for good reasons at the time. There are some pretty obnoxious vulnerabilities like the print spooler bug or the netlogon vulnerability that pop up from time to time that take a long time to patch in the field too.
