I like playing a pair of Back to Basics as I think the card is well positioned at the moment it is good against Urzas Saga decks and Green-White Depths has increasingly become more popular as it gained Yavimaya, Cradle of Growth from the new set
If you play this on turn one and then play a fetch land and basically anything else on the next turn, youre off to a great start
If X is only 5 then you played the best Cultivate ever printed for 5 mana
This is generally a bad idea as you should be building your game 1 mana base with your optimal curve/color distribution in mind, which doesnt change just because youve suffered a bad bout of variance
If you would get one or more counters, you get that many plus one of each of those kinds of counters instead
I can imagine a metagame where Vivien had a chance to shine, but the most likely scenario here is that she becomes another $7-$8 five-mana planeswalker in a long, long line of them