Problem is, that means I'm forced to drag another mage everywhere. I like to be self sufficient, I don't want my barriers to be weaker because I left someone at the keep. Besides, that would mean my companion would need to focus on spirit, which is bad because I want companions to focus on direct skills. I'm focusing on barriers so nobody else has to. Every point I put into spirit is a point a companion mage has to focus on other areas. And this is on this character. My other future mages, my rift mage and necromancer, will probably not use barrier that much (barrier will still be used, but a companion will have that job next time). I'm trying to make a tank mage with my Qunari. Once that role is done, on future playthroughs I'll ignore barrier for myself and be more focused on controlling or killing than surviving like I am for my KE.
This mage playthrough- tank, durable, very very hard to kill
next mage playthrough- necromancer, controls the battlefield and enemies to make enemies unable to fight at their best
next next mage playthrough- rift mage, focus on massive damage and power and obliterating enemies
See? Focusing on barriers is my theme for my first playthrough. And like I said, those spirit powers will be some of the last I focus on. I'll start working towards that when I'm level 21/22 and already have KE and winter pretty much maxed out. I won't be super broken up if I fail to get those passives.
A couple of things and then I'm going to leave you alone because it's obvious that the reasons you do things have nothing to do with game play, but are driven by thematic, role-playing visions that you have in your mind.
1. You are not a tank. You do not have taunt, your barriers do not gain any sort of advantage from mitigation making barrier intrinsically weaker than guard. No matter what you do, unless you play on an easier setter (maybe normal, I don't know. No advance review copy for Varus), you'll likely still need a real tank in your party. Your "tank mage" is redundant.
2. Specializing all of the barrier skills onto one character just means that your build finishes slowly. If you spread the "pain" out across a second mage then you can gain access to all the barrier goodies that you prize so highly (for whatever reason) so much quicker. And since, as I tried and failed to point out earlier, you have no means of extending barrier duration beyond that which all KEs have access to (and will take) then staggering barrier casts is your best bet for max up time anyway. Additionally there will be times when barrier is needed for someone other than you (that tank I mentioned, or another party member about to bite the dust). A spare barrier in those instances is huge. So "dragging a mage NPC around" is in your best interest. Suck it up, you have 3 to choose from.
So there you have it. Two excellent suggestions for you to disregard on why a 31 point build focusing on barriers is a bad idea. Having said that I encourage you to do so because you'll probably enjoy it more and it's your game. I only argue with you for the benefit of the impressionable youth who might be reading, lest they be lead astray.