Its a bad idea and i would disagree even harder by saying they should remove the warning on pykes ability, and they also should remove the visual indicator of kaynes shadow form wall walking.
All of those "warning" mechanics, are just casualising the game, making it more newbie or bad player friendly, and overal causing a less competetive and skilled environment.
If people die to those things, if people die to twitch beeing invisible, then they do die because they do not have enough understanding of the game and not enough map awareness, and no sense or gut feeling for such things. So they must improve, rather than nerfing the mechanics they fail to do well against.
I know this sounds hard. But theses days warding and getting vision is so easy, the same goes for checking where the twitch jungle starts, warding his clearing path or getting some deepwards.
There are so many indicators which tell you that someone is approching, its allready enough.
You can ward / deepward.
You can use your jungle experience and the actual meta knowledge to keep track of where twitch and kayne etc, start to clear the jungle, and use the respawn timers and vision u have to estimate which paths twitch will possibly take next or where he will gank next.
All of those player have movement patterns which can be fairly predictable.
You can read your opponent laners movement. Hes often telling you a lot about where his jungler is at the very moment and if hes approaching you or not, a laners are giving you warning signals for upcoming ganks just because they cant keep their pokerface in lane.
And many more small things...
If you can not read those things, it means you must improve as a player. You are not good enough yet.
Or you are just unlucky, or the opponent did play / path / prepare the gank, really well, (which obv. should pay off)
And even if you get ganked or are beeing caught. You should be able to escape.
If thats not possible it means you were off position.
You played in a way that enables them to gank and catch you easily, otherwise you could escape.
If not, this comes once again back to the argument that you need to imrpove yourself as a player.
All of this comes down to a point where u can be HAPPY about a twitch approaching you, because you KNOW hes coming and you can take advantage of that by just turning the tables and get a kill on him with the right kind of behaviour.
And even if you do not manage to go so far, escaping is enough allready, since you wasted and soaked the opponents team jungler or attention of 2-3 players and delay their xp / gold gain, their farm routes and giving other players of your team and especially your jungler, if he didnt counter gank ( which he should do if hes good ) more time and space to achieve something elsewhere.