Believe it or not you actually can tank as a Vigilence, tanking is mostly gear not the actual skill trees.
The hybrid build is also supposed to be effective, but I didn't go that route. You will get more threat as a hybrid though (you just want to use overhead strike a lot).
I've done both on my Jugg. And for tanking, I prefer the hybrid. It allowed me to get stasis mastery and still have OHS (which I've read builds more threat than both Guardian Slash and Hilt Strike combined, although I've never tested it out). If you go full Vigilance, then stasis is used more as an additional interrupt, and then only on normal mobs, etc. I've found that with the hybrid, controlling a group of enemies is easier, since I can throw stasis mastery on one and attack a different one.
Plus, I also have Shien that way, so I can be a decent dps when I'm not needed for tanking duties. Granted, I have two sets of gear for this, but it's a simple matter of just changing out the gear and switching stances. I don't have to worry about respeccing for smaller things.
As to your question about Guardian abilities, many of them are very situational. Some I very rarely use, and some I use only once a fight. Others (OHS, Blade Storm, Riposte, Master Strike), I use over and over again.