Before her recent changes, I played a lot of Taliyah and abused her ultimate well. Every time I used it, I got either flashes (for them to get over the wall) or kills for my team. Literally all you have to do to effectively use this is press alt, click, and move your mouse to the "On my way" ping a few times before you send it in and then wait for your allies to engage, then follow up engage with it.
Shen I'll admit it more difficult to use effectively because he requires a target. Map awareness alone often isn't enough for a Shen to be able to use his ultimate, it requires more communication than that.
However, Shen and maybe Rek'Sai to an extent are the only champions with global presence that have to have communication to be played at maximum effectiveness. Taliyah, Twisted Fate, Sion, Nocturne, and a ton of others can be used to great effect without any further communication than the "On my way" ping. I know because I've used all of these champions properly with only the On My Way ping. To say that you can't use these champions without a call is very false because it's beyond easy to do so, in most cases. GP isn't the easiest one to use, but I have been messed up in a lane fight by a GP ultimate so many times it's ridiculous. And remember, I'm bronze 2. Having the map awareness to use these abilities properly isn't a difficult thing at all.
Now, also remember that Twisted Fate was once one of the most broken champions in the game. The teleport was on his E rather than his ultimate and his ultimate was a global reveal and slow that made his E instant cast. Oh, and Gold Card did more damage, was AoE, and the stun lasted 1.5 seconds on a 3 second base cooldown at max rank. And his passive gave his entire team free crit chance.