New Races: Add or Replace?

So, my latest RPG-related undertaking is to build an entire world from scratch, and have it compatible with D&D5E. I am doing this in the hopes that someday in the distant future, after my wife is done with her Dragon Age campaign, I can take a turn behind the DM’s screen for a while.

The concept of my world is pretty simple, and not all that original. But, it allows me to have the world I want, which is what this whole DM thing is all about, right? Basically, I’m pulling ideas and concepts from various other worlds, mixing in a few of my own, original creations, and building something that is fun and whimsical, yet with an underlying darkness.

Anyways, one of the first things that came out of my brainstorming for ideas was the notion of new races. Now, the PHB has a laundry list of races, and sub-races, so it seems like adding more in might crowd the playing field a little bit. But, I really like the races I have come up with.

Some of you may recall an earlier post where I detailed my first 5E creation, the dwarfling. Well, I like them so much, I’m putting them in there. And the other day a new race sprung out of my head (highly influenced by Wildstar MMO race, the Granok), called the ferrusans. The short of it is that dwarflings are a mix of dwarf and halfling parentage, and are highly personable and charismatic. Ferrusans are the descendants of earth elementals who were trapped on the material plane and forced to take a mortal form to survive. I’ll post my write-up of the ferrusans at a future date.

But, my question to you is, should I simply add them to the lexicon of races from the PHB? Or should I maybe replace standard races with them?

I’m inclined to go with just adding them. But, I have to admit that using them as replacements might be a better way to go. In their first incarnation (for 2E) I envisioned dwarflings as a replacement for gnomes. However, I kind of like gnomes now, so I’m torn. Maybe replace tieflings?

For the ferrusans I would probably replace the dragonborn. I briefly thought about replacing half-orcs. But, my world would not be MY world without my beloved half-orcs. So, if I go that route, it’s bye-bye dragonborn.

Lots of other details are slowly being fleshed out. And like I said, this is something for a far future date. But, I’d be interested in your thoughts, fellow adventurers!