Yes, those last three picks you mention were because of the really high curve I had, and in particular theOwl was for the silence.
You shouldn't overreact to your curve. It's okay to take an average card over a great one, or a below-average card over a slightly-less-below-average card, but there are some cards you just don't pick regardless of curve. For me, the "never pick" neutral commons are: Thrallmar, Dalaran Mage, Shieldbearer, Boar, Footman, Silverback, Magma Rager, Dragonhawk, Wisp, and Grimscale.
The point of having a "good" curve is that you want stuff to play so that you don't waste your mana. The problem with things like Dragonhawk or Boar is that even if you do spend your mana on it, it has no impact, so you might as well have just not spent the mana. It really doesn't buy you anything most of the time.
Otherwise I'm going mostly by suggestions in various places. Almost all the epic rankings put the Captain far down unless it's a constructed pirate deck.
Then whatever rankings you're looking at are kind of questionable. A vanilla 3/3 is an acceptable 3-drop. It trades with all 3-drops other than Scarlet Crusader. I think the Captain is unquestionably ranked 5 out of 10 neutral epics.
Good-Great: Sea Giant, BGH, Faceless, Blood Knight
Average: Captain, Murloc Warleader
Bad: Molten Giant, Doomsayer
Unpickable: Mountain Giant, Crab
It's hard to justify Owl over Scarlet Crusader in general. Owl has great utility, but it's very situational and sometimes it just never gets used effectively. I often try to pick one up if it's not a huge value drop, but SC -> Owl is a massive drop in strength.
I never take any neutral above Scarlet Crusader other than Sen'jin or Yeti. Like ever. Scarlet Crusader is the business in area. Pyromancer and Knife Juggler are rare, so the only good common answers to Crusader are Earthshock, Arcane Missiles, and lucky Mad Bomber. It's really hard to not gain an advantage with Crusader.