No, it's not necessary.
The item would be to strong, to have a Banshee's on command.
Which is the point, and why the item you want doesn't exist.
And I didn't suggest an entire support build, I said from the list of items I gave you can find the right combination for the right situation. Well, apparently YOU can't... but others certainly do.
What you want is an on command get out of free card... but that's not going to fix your poor positioning or you lack of warding that is getting you caught to the point that you NEED a Banshee's on Command.
I haven't heard a single Pro Player say this item you described is 'necessary', or even ask for an item like this... and they seem to get along just fine.
So I ask... WHY is it needed?
Simplest answer... it isn't.
And so you know, I've been playing since Pre-Season 4... you've been playing since Season 4 (possibly Pre-Season)... to which I have a crap ton more games and hours invested. But please, tell me how you are 'more experienced' than I am that it tells you such an item is needed.
You have 37 Ranked Games since Season 4. I have over 100 Ranked Games on Multiple Champions, and over 200 on at least one (Leona). Not sure where I don't 'have the experience' to know this Item is needed or not. And all those Pros who've been playing way longer than either of us... guess they don't have the 'experience' to know your item is needed either.
What you want is a cop out, a get out of jail free card. One shouldn't exist, especially with Cleanse, QSS and Banshee's already in the game.