At the release of a new set, card evaluations are all over the place. It's impossible to know exactly where any card will land, but speculation is a good way to practice your card evaluation skill. You think of why a card would be good or bad, and then when your evaluation is off by a bit, you can learn a lot from understanding the calibration.
Here are some cards that I believe will be overrated at the beginning of the Limited format:
The base case for Wildgrowth Walker of a 1/3 for two is bad, but with a good enough ability you learn to tolerate a mediocre body. And a +1/+1 counter and three life, as an effect that can happen multiple times, is extremely good for a two-drop.
There is one problem, though: Explore is too good.
Remember U/R in Magic Origins? The archetype was supposedly built around Thopter tokens, yet that almost never happened. This was because every single card that made a Thopter was very good. It didn't matter if you were in the archetype; if you played either red or blue, you prioritized them highly. I expect this to be the case for Explore.
Scrying is a very powerful effect, and Explore is, in almost all cases, better than "scry 1." Looking at the cards previewed with explore, they all seem like top-tier Limited cards. You either get a slightly overcosted body with the text "draw a land" or a slightly undercosted body with the text "scry a nonland card." Both of these options are so good that getting a density of Explore creatures will prove difficult; hence, Explore build-around cards get substantially worse.
Five-mana removal is no longer good enough. Creatures we're getting of late have been extremely efficient, and the only reason to play clunky removal is out of necessity. Sure, you play the cards, but I haven't been happy first-picking any of the five-cost removal spells in the last couple of formats.
Now, these are cards you still play, but I would be looking to take this card around Pick 5 or 6. The ability to burn a player out, while relevant, won't come up all that often. And as often as it does come up, so will the downside of damage-based removal with Enrage.
I think all of this adds up to an okay Limited card, but nothing to write home about. This card will be over-evaluated in the beginning of the format, so a late one can be read as more of a signal. But you won't see me prioritizing it.
People love their countermagic. Many people took Supreme Will highly, but that card was never impressive (and is much better than Lookout's Dispersal in the average Limited set). Three mana is too much to leave up, so you end up forced to counter spells you don't care about in order to not fall behind on tempo.
Essentially, without a good number of Pirates, I'm not interested in this card. And a couple of Pirates won't get there either. I would need this to be two mana consistently, because that is a much easier amount to represent. And if you have a ton of Pirates, perhaps ten or more, this card could be quite good. But it's still not amazing by any means, as you'll never be able to cast it on turn 2. One of the biggest advantages of cards like Mana Leak in Limited is the ability to counter a three-drop on the draw.
Overall, this is a card I want to take on the wheel. If I'm in a dedicated Pirates deck, it gets better, but it still doesn't seem to be something I want to prioritize.