I am currently dungeon delving in Od Nua and I replaced Edér with Kana (for his quest), and Kana is just a so much better tank than Eder while also dealing massive damage with Dragin Trashed. And summons on top...

Only, I don't plan on keeping Kana for long, so I wonder if I would be better off making Aloth my second tank next to Pallegina? I don't feel very confident with only 1 tank in my main squad, I tried that in Od Nua 4/5 a bit and it was rough. Without Eder (or better: with Edér as my switcheroo companion), I would only have squishies in my main team aside from Pallegina, so I would like to make one those squishies into a tankie  It's pretty much Aloth or Hirvias, and I don't see any mention of druid being a decent tank anywhere..?

I read a few bits here and there that aloth CAN work as a tank, just couldn't find any guide for that..? 
Would making him into a tank be too extreme/niche? Or would I have to ditch all his other roles for it? Currently he is pretty much my main debuffer, with the occasional damage output, but mostly debuffing. I wouldn#t mind making him a tank+debuffer, but sacrificing both roles he currently fills seems meh to me. I asked my buddy if he knows anything, but he only played a melee Aloth in Act 1. 

I helped out and tested Aloth as a tank, mixing existing builds (Bilestomper, Frozen Lance) as guidelines.

Now I use Aloth as a tank too... xD

After the first levels a Wizard can tank quite well (once he has sufficient spell uses at his disposal). At higher levels it's a good use of low-level spells (many defensive self buffs are low-level spells that can even be mastered) because damaging low level spells like Fireball etc. lose effectiveness against higher level enemies anyway.