Was i too impatient?

Maybe, but never assume for sure you'll get that unit on a legendary banner. If you use BK enough and weren't planning on building Buff Ike, then nothing too much to be upset over. Also just helped bolster BK's biggest weakness.

IDK man, at least I've been really lucky, getting 4 5 stars in 150 orbs on the Legendary banner, a Shiro and Gunnthra, BIke, and Dorcas. I've summoned 70% blues, but there is SUCH a lack of Blue stones, the classic 'hah you want Ephraim or SCorrin, NOPE' and then I end up getting a 5 star on a rare green orb.

That said? I think you're good, plus that makes Black Knight better able to take on the popular trio of green dragons, it's almost guaranteed one of the three will be on an arena team.

I immediately foddered my Ike off to Fallen Robin for Warding Breath (was also kind of annoyed that Ike won the voting, but it's a free 5* so whatever). My Fallen Robin is going to be a main stay on my armor team and I already use him quite a bit (already gave him armored march too). If you use your Black Knight a lot then I feel like it's no issue that you gave him Warding Breath (he's better than Legendary Ike in my opinion and with this he can take on green dragons more easily). If you don't get another Legendary Ike it doesn't really matter as there are so many other better sword lords out there anyway.

You're good especially if you were looking for that special charge...His physical bulk is already pretty good but his Res is so low I'm not sure the +4 helps any of his matchups

Considering that you’re going for blue only in the legendary, you didn’t do anything wrong. Only question a decision before you make it, not after, especially with SI.

I would of kept him, but I like the atk blessing, really helpful on brave weapons and reinhardt