Yep, it's screwed. Basically we're going back to the TBC range checking system where there are built small set of ranges you're allowed to check for. Like 27 yards, 16 yards, 8, 3, etc. The range of things like Inspecting and Bandages. Your addons can now only check those ranges, they can't get exact range. So now say for instance you want to check if a player is 30 yards away for a 30 yard range spell.
No bueno, you can only check if they are 27 yards, so you'll either not get a range check at all, or the creator will decide to say "Sure, he's within 30 yards" if he's within 27 so you're actually up to 3 yards closer than you need to be by the time the bar highlights. This could cause unexpected deaths because a dying player could be 29 yards away, within range, but you think he's out of range because the addon says he's too far away since he's past the 27 yards it can check for.
Have fun when a boss requires everyone to spread out 10 yards from each other but your addon can only know if someone is within 7 yards and can't display position so you just get a text list of people within 7 yards. You then have to read their name, look at your screen and see where they are standing and move until they drop out of your range list (all within the few seconds before the boss does his spell), turns out they're only 8 yards away now (just past the range check distance of 7 yards) but that's still too close for the boss mechanic, boom you're dead.
If you raided Gruul in TBC you'll remember this little bastard of a range checker that hardly helped at all.
Well he's back, because they've essentially just rolled back addon unitPosition logic 10 years and put us back in TBC.
Also don't drink their koolaid on how they can now design fights around not needing them. Legion raids are full to the brim of these mechanics that beg for radar HUDs. In fact most feedback threads during beta test raid weekends were people asking for addon updates because it's way too much to keep track of without.
If they really cared about drawing arrows and whatever they would have broken the GetPlayerFacing command which would have made drawing arrows to positions and knowing exactly where a unit was impossible but left alone the ability to check exact range from a target.