I think the main problem with Half-Elves and Half-Orcs in the D&D/FR setting is that they never really did the legwork of establishing those as discrete types, like with independent races/cultures/historiess
Given the origins of both races, is it problematic?
Orcs - by their very nature - are ugly (relative to humanity) and savage (i.e., Chaotic Evil nowadays); rare is the human that would want to mate with an Orc (perhaps barbarian tribes whose territories abut Orc lands?). The overwhelming majority of Half-Orcs are unions born of rape. Half-Orc societies are correspondingly scarce as hen's teeth.
Elves are beautiful and noble; there is no shortage of Humans attracted to elves, but Elves don't often reciprocate that attraction. Putting aside the more elitist Elves who would never deign to lay with a Human, your average Elf is a passionate individual who would deeply feel the loss of a short-lived partner once their time is up and so they make the decision from the outset of adulthood to never engage in such a romance. Having said that, Half-Elves would be more common than Half-Orcs because Elves are much kinder than Orcs.
The only major Half-Elven society I can think of is in Aglarond (thirty-percent Half-Elven).
