While The Brothers' War meld cards still run the risk of having a part of the meld pair removed in response to the meld effect, most of the cards doing something pretty much as soon as they meld is a big improvement on the original cards
For formats with fast aggro decks, it might be better to play a Branchloft Pathway on turn one to make your Noble Hierarch, or as Boulderloft Pathway sometimes setting up your Collected Company
Attaching Team Rocket to anything will always ensure its popularity, so adding these cards to any collection will only increase the value
Birds, which all flew in this set, had a "nonflying matters" theme, which contradicted the desire for an all-Birds deck
Iona is a 7/7 Legendary Creature with Flying, and when she enters the battlefield, you choose a color, preventing your opponents from casting any permanent spells of that color
The metalcraft ability pushes Ezuri's Brigade above rate fairly easily while the base power and toughness is still high enough to enable cards that care about those stats, like Garruk's Uprising