Abilities that cost mana to give you mana always weird me out, adding in the land bounce does or more so. But I don't see anything wrong with this yet. It's hard to theorize what that land bounce will do.

Looks scary to me. Imagine some Azusa, Lost but Seeking / Exploration deck. Quirion Ranger is quite good on its own and the ability is hardly anything because of the untapping.

If you don't have any lands to drop for the turn, this seems extremely good. Tap a land, return it to your hand, play it again and tap it for mana - net loss is , but the ability grants you two mana of any single color. That's a pretty crazy thing to do for an 1-drop.

It's nice. Every land can give you double mana - including colour fixing; but only once before you need to replay it.

Which feels sensibly powered. But the terrifying "Ok, turn three, I sweep, and play my combo" is probably overpowering. Anbd that's before you get into 'play an additional land from hand' cards to combo with it.

One-sided Boom // Bust (Bust specifically) from turn 3 forwards? "Nice".

Well true; you're taking a big risk. If the opponent counters your big push, you just destroyed yourself completely.

Does having that possiblitiy make for fun games? I dunno. We haven't seen the sweep mechanic since kamigawa days; it wasn't all that popular then, though.