Necessarily? You don't get any choice in the matter? That's a useful trait on an expensive card, but on a 3-drop it seems like a drawback.

It's also unworkable - how can an opponent be sure I drew it, rather than having it in opening hand?

Still not sure I'd play it. I guess it'd be okay if I only had 2 lands, or 1 land and some 2-drops. But it's such an underwhelming creature (blue gets it for 2 mana, Lumengrid Warden) that it feels hard to justify putting it in a deck.

There are assorted discussions on Street Wraith, Gitaxian Probe, Urza's Bauble and so on - couldn't you just play them all and shrink your deck size by 16? The conclusion is "yes, but that makes it impossible to mulligan sensibly". This is nicer for the mulliganing decision (because I assume you can use this ability before choosing whether to mulligan), but much less good if you draw it during the game.

Hmm. How about if it had "When ~ ETBs, you may discard a card to draw a card" as well? The two effects mirror each other, but then it's providing a tiny bit of card selection along with its unimpressive body if you draw it on turn 4.

The main reason not to add more to it is that currently it exists to make the core deck better in draft without being to easily broken, also it is just a common, adding more makes me think I would have to bump it up in rarity to uncommon.

Could it then be 2 mana? Or a 2/3, like Riot Devils? Just something so that you don't feel so very embarrased to be spending turn 3 casting this...