Pointed Discussion

Decent mana-fixing.

1 card for 2 (basic) lands is pretty good in any deck not running green.

Solid land finding in non-green.
It works for me.

I wold recommend swapping these out for Expedition Maps immediately. Even when you need two lands, fetching a Ravnica bounce land is almost as good. Plus, it can be played on turn one and nab Command Towers.

Wizards is so keen on this card.

I think my biggest problem with this is it basically costs four mana to use, to get you two lands in your hand. That can slow you down pretty significantly. Though I suppose if you can't splash green, something like this is a decent alternative.

Absolutely bonkers in draft. Anyone that was able to get more than one pretty much won their games.

It does it's job of bumping you up to 3 or more colors well. Two of these, and you have Domain. Similar to Mycosynth Wellspring.

My Kazuul commander deck can't run Ravnica bounce lands and has no use for Command Tower, but it does like ramping up for Koth or Moonveil Dragon, and it can put out more lands a turn with Terrain Generator and Walking Atlas

@armogohma's comment: In many cases, library-thinning with multiple Spheres would be preferable to multiple uses of the Map; and a single use of the Sphere generally widens your on-the-board mana base at least as much as Mapping a single Ravnica bounce-land would - and it does so at a slightly faster pace, because you'll often be able to immediately use one of the two basic lands you siphon using the Sphere (besides, two basic lands produce more mana than something like a single Command Tower or Rupture Spire). As you yourself pointed out, your own suggestion is "almost as good" as the alternative! The only difference would be the 1 cost versus the 2. However, you'd still need 2 to activate the Map. Again, the thinning matters; unless the game is pure speed 1-on-1, and your deck has no or little other capability at increasing its own pace relative to the opponent's (if you're playing speed 1-on-1: it should have other forms of pace boost). If the situation is EDH/Commander, then you'll probably just want to run both, if either at all.

This seems pretty powerful - probably competes with Darksteel Ingot (and even Gilded Lotus) among artifacts that support multi-colored efforts - which can be more helpful or simply better in many decks than Green's abilities to provide similar assistance (because, for one thing, not all multi-colored decks are able or wanting to include Green).

However, in decks that do contain Green - and even in mono-Green decks - the Sphere has great synergy with the solid and playable Explore.

Look at it this way; in Commander you have your big ol' deck with 99 cards, and chances are you have a certain number of cards you always want to hit.
For 4 mana, you get 2 basic lands and thin your library by three cards.
I like it.

This card is an all-star for any non-green edh. If you're not running this along with Expedition Map, you might be doing it wrong. Generally, nobody messes with it, and it will keep you dropping lands until you get to the 6 and 7 drops. This card has saved my butt so many times in the early game from just falling flat on my face, seriously. And even if you have the lands you need, you can pull out 2 dead draws from your deck and just keep chugging towards the mid or late game.