You can control your TU and type of weapon, so don't say tactics is not important with melee now. I'd say it's more important than ever; no more dumb "run from the front of someone, brush with him, position yourself behind and unload 50 attacks without any risk". Stats of course, matter a lot; else there wouldn't be any, lol.
But I expected fierce resistance to this change, so well, I'm not surprised there is.
You already fixed the "run from the front of someone, brush with him part", since melee reacts to all frontal quadrants now. That change is awesome, since CQB is a lot cooler when units guard areas with melee now.
I didn't say there was
no tactics, just that units reacting to back-hits places much more emphasis on stats and equipment tiers, than facing/positioning. With melee, you're already trading in TU and greatly increased risk to get behind, vs the safety of shooting from a distance and moving in/out of cover. So chain-sawing someone from behind felt fun and fair.
Never saw an issue with unloading TU on someone's back, because that's what would happen logically, IRL or fantasy. IE: An uber mutant choke holds someone from behind, while shanking their liver 50x, or braining someone in the back of the head and not stopping until it's pulp. You could play out the fantasy of a naked berserker/silent ninja, using only their animal cunning, savagery, and something grabbed off the floor, to efficiently take-down targets with magic/alien tech who instagib gals when they so much as look at them.
By the same token, your own characters not reacting to back hits, makes the player want to cover their backs, not be over-aggressive, and make sure they never get hit from behind.
For the player, this made facing even less important. Now you can more freely/carelessly place armored up units without caring which way they face.
Like you couldn't expect not to get hit when meleeing a blood hound with TUs. But the turning around bit for some is the question.
Always saw this as an accurate representation of: uber mounts monster from behind. Same reason why hitting someone in the back is illegal in the UFC, or why giving up your back is the worst possible outcome.