you just banned growth spiral this is the exact same thing one mana more but throws in life and a counter for a creature on the bright side its sorcery so probably not as big as a risk
but this is amazing for a common I would think of it as a uncommon
A big part of Growth Spiral's power was being an instant, so you could hold up or bluff a counter and then cast spiral at the end of their turn. Tapping out on your turn to get the same effect isn't nearly as strategically strong.
Remind me why Timewalk is P9 and thus is a common?
But... What if you have no creature, no lan in hand, no card in your library and you are at to life with your opponent having a Tainted Remedy out? What then huh?
Also, what rowanalpha said.
Well sure, but Timewalk does nearly nothing in that same circumstance, except for not kiling you to Tainted Remedy. Like 90% of the time extra turn effects may as well say "play an extra land this turn, draw a card". But to some degree, I am exaggerating for effect. I think this is fine at sorcery speed but would be a risk at Instant. As stands I'm not sure it beats out Cultivate as the 3 Nana ramp of choice in Standard.
This card is much worse than Growth Spiral. 3 mana vs 2 mana for this effect is huge, and needless to say instant also meant you could hold up interaction, see what they play then decide to Growth Spiral if it doesn't bother you.
There's a lot of text here, but most of it is irrelevant. The sort of decks that play this sort of ramp don't play early creatures to put a +1/+1 counter on anyway so you won't have a target most of the time. By the time you are targeting Uro with its effect, the effect is negligible at best. Gain 2 life is marginal at best. All in all you're paying an extra mana for a slightly better Explore which isn't going to be worth it. Especially as the 3 mana slot of these decks already has Uro and Cultivate.