I know I'm in the minority, but I really don't see any benefit to side armor. The front/rear mechanic is sufficient to encourage players to flank. Frustrating cases of scatter and RNG can be addressed without adding this mechanic.
The scenario he keeps bringing up is of tanks facing each other at a slight tilt and by a freak of chance, the rear armor is hit from a mostly frontal shot, because the rear half of the tank is sticking out in a thin slice. This is a valid (although very rare occurring) problem that the current armor system can't fix.
Hitting the front armor from a rear shot is equally frustrating.
The inclusion of side armor would mitigate these edge cases (although it wouldn't guarantee the desired result) but I don't trust Relic to properly maintain the added level of complexity. Just look at how difficult it has been so far for them to handle the new building panels and target tables.
Let's also excuse Relic on that front and admit that bugs are simply inevitable. Well the horrendous patch rate would still be a problem. I would not look forward to T34s consistently bouncing P4's side armor not getting fixed for months.