If I could have named the one thing to avoid in creating psionics for 5E, it would have been tying it to the Far Realms -- actually, there's an 80ish page thread where I said that a couple dozen times.
So, yeah, I'm unhappy. It's stupid and I hate it. I don't really even want to use the Far Realms, but I like psionics. Please don't confuse my new players and make life more difficult for me. Likewise, if I'm playing a psion in someone else's game, please don't have the default flavor be something unsavory. Also, there is no Far Realms in Dark Sun, so why did you just do that?
This is unambiguous, and bad: "Psionics indirectly originates from the Far Realm."
This is better, but still not quite right: "Psionics is more common in worlds where the bounds of reality have been twisted and warped to stray far from the baseline D&D setting."
Let me suggest the following lead paragraph to the
Otherworldly Power section:
Not every D&D world features psionics to the same extent. Psionics is most common in places where the bounds of reality have been twisted and warped. The realm of Athas in the Dark Sun campaign setting is the iconic example of a world where psionics is common. The gods are absent, magic has been twisted into an ecological scourge, and the common threads that bind many worlds of D&D have been sundered. By contrast, the world of Eberron is a setting where the bound of reality have been tested but not fully broken. Psionics is not as pervasive in Eberron as in Athas, but the influence of the otherworldly realms of Xoriat and Dal Quor make it a known and studied art. One common catalyst to psionics is the Far Realm, a dimension outside the bounds of the known multiverse. In other settings, psionics may be the result of magical experimentation, exposure to artifacts, or the nascent god-soul possessed by some mortals.
Take everything else about the Far Realms and put it into a sidebar. There's no loss of content or DM aid, but it does take out the hardwiring. (WotC legal: Please, feel free to use the above or some variation of it w/o need for compensation or attribution. I'd rather just have a better product.)
As far as mechanics go, it looks nice. I really like it, which surprised the snot out of me, considering the second big way to screw up psionics (IMO) was to include the "psionics are different" option as the default. I'd still really prefer "psionics are the same", but the way the sample powers are structured are enough like a Monk's ki that it's tolerable. Tolerable, but not great. Easy enough to house rule, though.
Tremorsense and
seize the initiative are easy enough to see as mundane-ish, but
broken will and
psionic weapon should cease to function in an anti-magic zone and be dispelable.