Well I really liked the original Myst. It was not overly complicated. I also liked Riven. I played Schizm, Reah and the series by Rhom.
If you're looking for games that are similar to the Myst/Schizm/RHEM series (similar puzzle types and difficulty) and not simply any game with 1st person point of view:
These aren't new and you may have already played them, but
Schizm 2 (Mysterious Journey 2)
http://www.mobygames.com/game/windows/mysterious-journey-ii-chameleonSentinel (aka Realms of Illusion)
http://www.mobygames.com/game/windows/sentinel-descendants-in-timeAura
http://www.mobygames.com/game/aura-fate-of-the-agesAura 2 (The Sacred Rings)
http://www.mobygames.com/game/sacred-ringsUru (from Cyan, the makers of Myst)
http://www.mobygames.com/game/myst-uru-complete-chroniclesSlip Space: The Burma Shave Analogy
http://slipspacegame.tripod.com/Baron Wittard
http://www.mobygames.com/game/windows/baron-wittard-nemesis-of-ragnarokKairo
http://kairo.lockeddoorpuzzle.com/The Five Cores doesn't seem to be available anymore, and I'm not sure I'd recommend it anyway because of bugs. But it was pretty.
http://www.gameboomers.com/reviews/Ff/5Cores/5Cores.htmhttp://neebla-games.com/index.phpI can't think of any that are more recent, though of course there are older games with some similarity to the Myst/Schizm/RHEM types -- Obsidian, Myst III: Exile, Comer, Atlantis 2, Amerzone, Morpheus, Alida, Connections, Shivers, 9: The Last Resort, Timelapse, the first 3 episodes of AGON, etc.
There are some 1st person "horror" games that aren't overly gory, such as Dark Fall 1+2, Barrow Hill, Rhiannon, and the Last Half of Darkness games.
http://www.lasthalfofdarkness.com/Upcoming games that might interest you:
Obduction (from Cyan, makers of Myst)
https://www.kickstarter.com/projects/cyaninc/obductionXing: The Land Beyond
https://www.kickstarter.com/projects/1781324918/xing-the-land-beyond