First, I very much appreciate the consistent feedback! It's nice to have to think about my posts summat after I make them.
I ported some of the racial stuff over from another campaign I wrote, specifically the coloration of the dragonborn and the orcish feats. I'm not sure if you noted that the Greenblood grants half-orcs access to the orcish feats (which include an always-active weapon feat, though at present some of the others require the orc racial, which I might grant half-orcs another feat to take). I also understand that the expertise-style feats are big, but every 4e game I've played in for the last year or so has adopted the policy of just handing out expertise (now versatile expertise) for free, based on the thousands of internet-spawned words churned out about the combat gap issue. So the first part of my reason for including that sort of feat is, yes, an expectation that players will be allowed to make some more flavourful choices when less interesting things like expertise are already provided.
The second part of specific inclusions like that is setting related, for the half-elves and half-orcs. It's important to stress that there are no humans in my setting, effectively. Humans exist, but only in the swamps, mountains, and woods...they're all near-savages, and the vast majority of "humans" one meets are going to be closer to a shifter at the very least (with most of what you find in a human tribe actually being a reskinned gnoll, minotaur, goliath, squirrelman, etc). That's crucial because I'm not for one second trying to buy into the 4e revisionist half-orc bullshit where they're a "separate race." That's ridiculous. A half-orc comes about when a mommy or daddy orc and a mommy or daddy something else bump one ugly with one not-so-ugly. In the Tran empire, orcs have opportunity to breed with elves or dwarves (I could possibly see opening hobgoblins and bugbears up there too). If it's the former, though, it's going to be the result of military conquest, since the main thing orcs are doing other than fighting beastmen is trying to kill off those darn independent elves. Elves wouldn't raise a half-orc, so the creature is much more likely to take Greenblood and be a hulking savage who is perhaps a mite more graceful than his companions. Dwarven camp followers might give birth to a half-orc child, and occasionally a dwarven ranger might fall in love or lust with an orc and raise a dwarf/orc hybrid, which would actually find itself fairly well accepted in frontier Tran society. However, because the options are so very limited in terms of genetic mixing, I wanted to ensure that players were making their choice of parentage a significant part of their backstory.
It's the same with the half-elves. Again, with no humans to breed with, half-elves on the Tran continent are elf/dwarf hybrids exclusively. Some elves trade peacefully with the Tran, and elves are hot, so it's all sensible. In the Silken Kingdoms, since all the races represent the same core race (elves) further altered due to magical specialization/experimentation, mixing two already hybridized races produces offspring who favor one side of their parentage alongside the elven blood that they still retain. They can't take human feats (it wouldn't make any sense) so I wanted them to have an option whereby they can explore some races' feat trees...hence the dilettante swapping.
The third reason for my choice of feats like Greenblood is that I do expect the specific players I anticipate playing in my game to jump for this because I'm not a man with patience for min-maxery. Perfectly optimizing a sheet is fine for a delve or convention, where you may be on a timer and you're sure to be up against some utterly brutal encounters. However, in the 16+ years I've been playing DnD I've never gone in for character optimizaiton; I've always preferred character realization (was that lame? Perhaps!). That's true no matter what kind of game I'm running, but since I'm incorporating some rules into this specific campaign that make situations a mite less lethal (players have resources at their disposal to skip particularly dangerous encounters, though doing so will limit their options in other areas) there's even less call for the maximized approach. A half-orc in the Tran empire is going to be viewed a certain way and reacted to a certain way; I want her to have options regarding how much of that view and reaction is founded, and how much of each racial heritage is displayed.