They dont remove that at all. Because including Alolan Ninetales means you still have to work with just 4 Alolan Vulpix to make it all happen, all the while Alolan Ninetales GX is a greater allround Pokemon that will win you the game.
I personally do not think the format currently asks you if you can handle Safeguard. All it asks of you is if your certain you'd only want to rely on EX and GX and solely on EX and GX. Most decks do not have to do this. Most decks should run Guzma anyway. Again nobody currently is playing just 4 Alolan Ninetales for it's as much as a risk for the Ninetales player as it is for the opponent. 110HP is relatively easy to deal with for any non-EX/GX. It's attack is abysmal.
If anything Tapu Lele GX is the prime example of a card that alters deck construction, for there is not a single competitive deck in the format that wouldn't want to run it.
Drawing a paralel from Ancient Power to Safeguard really makes little to no sence. Ancient Power prefents some decks from doing anything. Safeguard at Alolan Ninetales and the upcomming Hoopa with Safeguard really has nothing more to do as being a wall.
To me Safeguard remains a fine balanced Power that ensures that multiple cards are a viable consideration that do not have EX or GX behind their name. This is a good thing because it keeps rogue decks viable aswell.
I believe you should say "nobody is right now." We won't know how powerful safeguard pokemon are until there are some tournaments with them. I *do* know how much harder it will be to kill them without Hex Maniac though. It will be similar to facing a Jolteon EX deck with big basics and they put one Jolteon out and get it powered up and leave their bench empty. Can you beat it with a big basics deck? Yeah, if you thought to tech Ranger. If you didn't? Toast. It is the same concept. It isn't a great deck idea to run a full on safeguard deck. That said, those decks do exist and if you are unfortunate enough to walk into one, chances are you aren't walking away with a victory because anyone good enough to build a competitive safeguard deck is also good enough to work over every halfhearted attempt to counter it. You know, kind of like how Wobbuffet Jolteon took 2nd at Roanoke...aka the regional quad lapras won.