At the moment I'm trying to equip my Wizard and I wonder what is the highest solo greater rift level you have been able to complete without Unity. I'm not going to argue if the Unity should be used as it is now, I just want to know how you do without it.
I have ~22M toughness (2.4K res, 8K armor, 675K HP) with all buffs and using deflection and still I get pretty much slaughtered by many groups on lvl23+, which I find quite odd with (in my opinion) this relatively high toughness. I don't think my build is the best I can make for a Wizard, but I'm currently just interested in survivability, which is to my surprise quite poor on this level.
I play with unity, so I wont be able to give the answer you are looking for.
With that much toughness, you can't have all that much dmg right? Could you link your profile, I am interested in what build you play with what gear, because I only reach Rift 26 and after that I don't have enough dmg output to kiil the rift guardian in time (last time I tried I was 4 seconds late).
But I think that your toughness should be enough, of course it depends on your playstyle (as example, if you play a meteor melee build and without CC, you'd be slaughtered even with 30m toughness)
The usual playstyle of mages is "kill them before they reach you" so basically, if you get more dmg your survivabilty will increase because you won't take dmg from most white mobs and elites can be kitet/CCed with Black Hole, mirror images etc
Edit: also, your weapons bonus is useless for you, don't you have another weapon with similar stats but a usefull bonus?
I won't pretend that I can't be a bit affected by my Barbarian. I'm trying to maximize my DPS time on mobs, but still move away from stuff. I'm not kiting all the time, so yes, monsters usually manage to get close to me. I'm using Mirror Image and Black Hole pretty intensively.
The weapon I'm using is mainly because of +arcane damage, however I probably don't have any other with something more useful or with more interesting bonus.
It's a great weapon, the secondary affix is useless but it doesn't matter, everyone is using GoO because of its arcane bonus. Don't worry about that. You want to find a way to improve your gear though...
1) In terms of toughness, your biggest obstacle is high HP. 22m sounds great, but 22m at 675k HP is not that great at all. It's "fake toughness"; you're not really mitigating a lot. 300-400k HP are fine, rather get more mitigation (AR/armor). You're wasting lots of stats here.
2) You've got some strange combinations of gear, for example, a sub-par two pieces of Vyr's which are useless. You could replace those with we-rolled crafted Asheara's Gloves and Captain Crimson's legs (you really want a high 550+ armor roll on legs, it's almost a must-have). Forget about Andariel's Helmet, it's a glass canon item; when you're dying too often Andy's is the LAST helmet you want. Rather get Aughild's. Actually, I think I'd recommend to craft Aughild's chest and helmet (on chest get 550+ armor roll as well, Disintegrate damage on helmet); Captain Crimson's belt and pants (high armor here as well) for the 10% RCR, and Asheara's gloves. In the long run, you can aim for a Tal's chest or of course Firebird's once you get all the pieces, but it's better to use crafted gear than sub-par, non-fitting random legendaries.
Beaten lvl 27 solo with my hardcore wizard (15 (pinpoint barrier) - 19 (pinpoint barrier + unwavering will) - 26 (FA/PB + UW + AT/FW) millions toughness), but that is about the limit of what I can achieve as Rift Guardian is way too tough for me to kill it quickly and any decent hit will at very least take a half of my health.
Highest I got was 35 without unity, using an ancient maximus, because you get hit so hard whenever you do get hit, with illusionist, tele was always off CD. In the right map with the right placement the demons chain is a great dps boost. Although the GR boss goes down so slow I needed a huge timer headstart. After finding the second unity, replacing the weapon with an ancient sun keeper and ditching RORG for an SOJ it bumped me up to 39. I think 40 will be possible, toughness surprisingly isn't the issue for me right now, its the timer I just can't seem to get far enough ahead of it to down GR boss. I'm starting to see how density and boss RNG matters, when you miss beating the rift by mere seconds its really disheartening.