Most of that isn't true (Guard/Jugg tanks do have the worst threat and Shad/Sins have the best, but it's not for the reasons you indicated).
Shadows actually require the least outside healing of all of the tanks and have the best overall survivability. The only way this isn't true is if said Shadow tank has no idea what they're doing. The issue that many people have is that Shadows have the least stable damage profile. What this means is that damage coming at a Shadow tank will be very spiky but that they will end up needing to be healed the least (which is a combination of their self healing as well as less reliance on DR which always works for def/shield/abs which have chances to work). Also, they've got the best threat not because they've got the best damage; they've got the best threat because they've got good damage *and* have a number of high threat abilities that are used *a lot* to deal a lot of damage (Project gets 15% bonus threat, Slow Time and Force Breach are both high threat abilities).
Guard/Jugg tanks are the de facto worst threat generators and damage dealers. There's no question about it whatsoever. They're also the hardest tanks to get proficient with (Shadows are the hardest to get truly amazing at, but there's a difference between proficient and amazing and you seem to be asking about proficiency more than amazitude) because of said threat generation and the most complex resource maintenance. For survivability, they're actually in the middle of Shadows and VGs: they have a more stable damage profile than Shadows but more overall damage taken and vice versa VGs.
VG/PTs are the simple tanks: they've almost entirely devoted to passive mitigation (meaning you don't have to push buttons to keep yourself alive) and very simple attack priority (I generally call them the faceroll tank because you can really get away with just smashing your keyboard and playing one pretty effectively). Their threat is decent but not amazing (better than Guardian, worse than Shadow) and, for survivability, they'll end up taking the most damage of all of the tanks but have the single most stable damage profile of all of the tanks.
If you're not really looking for something for absolute top tier performance and don't really care too much about learning the ins and outs of tanking, I'd recommend going with a VG/PT tank: it's simple and effective. The only problem with it might be that you find it too boring to play and just get tired of it.
This guys right about everything except juggs have 2 tanking profiles the immortal which sound like your description and hybrid which is becoming the norm for jugs and is far more sturdy than the immortal.
Hybrid juggs have the mitigation of a PT but with the Cd of a shadow, but with the least threat of all the other builds. A hybrid has 3 Cd saber ward (50% damage reduction) 3 min , Invisible (40 %) 3 min, Deafening defiance (20%) 45 sec, and 4th if u want to count unstoppable (20%) 15 sec, and a 1 k absorption shield every 9 sec.
This makes hybrid juggs the most sturdy Tank in game. The least able to control big trash mobs but great at boss fights. Also Hyrbid Juggs are becoming a healers best friend in pvp. I myself have met some great IA that we have held location 6 v 2 till team re spawns, the trick is to keep jumping/ interceding, your now reduce a healers damage by up to 90% roughly at times.
This leads me to a power which make juggs different in pvp, and that is Intercede. It allows the jugg to add 20% damage reduction that's 20% more than any other tank can do. Now on top of 50% reduction on ally with guard, you have Intercede which is another 20% and another 30% reduction on target with taunt.
Explained, Healer (50% guard + 20% intercede) 70% damage reduction, Attacker ( 30% damage reduced taunt).
Healer and jugg Hold where other tanks fall in pvp.
All Tanks are good and are different, you will want to play them all I am playing shadow now and love it. It is allot easier because of the threat. There are times you play a jugg and your team just s*#ks that's where shadow are more forgiving. Keep threat easier faceroll, but the experience with a jugg hybrid in pvp, is one in itself worth it if you have the chance.
My opinion in for tanking purpose only.
Shadow pve (group friendly)
Jugg hybrid ( pvp dominant)
PT ( easy mode)
There all fun