I completely disagree with you. Sorry. Here is some of the ways it's NOT a faithful reboot.
1) Lion-O : They changed A) His muscle mass b)his age and c) what sounds like a higher voice. All 3 have changed the character dramatically. Remember "the test of strength" When he matched Panthro in strengh? Yeah I'm not buying that this one could at all.
Remember all the times he took charge or gave heroic speeches? That's because he he had a commanding voice. Like other leaders around the time e.g He-man , Optimus ect... This one doesn't seem to have that
By changing his age his "I need too prove i'm grown up" doesn't work as well. No matter how they deal with it he looks like a teenager so his problem there will seem like teen-angst not an actual problem.
This has a trickle effect. In the old one there was a few times the others overlooked him because he wasn't naturally that age. It was understandable and now if they do it it's normal. It looses something.
Snarf as a result will loose something. As a big part of snarfs character was seeing little Lion-O grow up over night and couldn't quiet deal. He kept bringing him toys ect... Now it's not the same even if they do scene for scene as it doesn't have over night aging.
All aesthetic that I actually like and support the changes since it's more in keeping with the actual character.
2) Thundera is part of third-earth : Stupidest thing I've heard yet. That's like superman movie in 2012 making Krypton part of Smallville not another planet. Stupid move it also ruins elements of the series.
The people coming from space won't be the same as any one from Thundera won't be. And if the mutants world is too that'll effect the Lunataks orgin and introduction too. this is the worst one yet.
streamlining the mythology is fine by me, definitely wont keep that "oh yeah that survived thundra too" plot device
3) The look of the show : It just doesn't match any of the original designs. It's like someone's anime fan art on deviantart. They look too different. You can make characters look similar see He-man. Or mix new and old well see 2003 Ninja turtles series.
This doesn't do that at all.
The original look was pretty gay, I'm glad I doubt always have to see LionO's abs and legs all the time. Still, Lion O is wearing blue has red hair, Cheetara is in orange with cheetah hair, Panthro is bald with spikes on his costume, etc.
And you can bring up that He-Man cartoon all you want it makes not difference. They couldn't even give the character pants, just that same hair diaper he's had for 30 years. It's like they didn't even think he's worth pants. Plus they did change Prince Adam's design to show a more significant change into He Man, so there you have a fundamental change to a character's design to support who character is.
Just those 3 things alone is enough to say its not "faithful" at all. Which is a shame as you can see on page 1 I was so excited for this till I saw what they were doing.
Honestly all you said are minor changes that are more aesthetic and done for a streamline story which really don't effect the heart and substance of the character, story, action, plot. In fact all the changes I see support those things more. Lion-o is still the young hero taking on the responsibility of a leader that he may or may not be ready for. I much prefer him to a young adult than a weird man/boy child due to some relativistic effect of being in suspended animation that didn't effect anyone else. Also the muscular design he had in the original was actually just lazy/fast animation, the majority of the regular characters had the same body drawn, lion-o, panthor, tygra had the exact same body structure, it wasn't until a few episodes and more funding in did you see new characters they have much more independence. Pantro body has been describe as a character with superior strength, Tygra was defined as smooth stealth, yet they have the same exact bodies as Lion O. The changes in design actually supports the character's individual talents, personalities, and character making the team a more diverse and functional unit.
Though I doubt anything anyone will say would change your mind, If you want something exactly like what was already done without any changes good or bad I suggest you just watch the 130 episodes of the original series instead. And the rest of us will take a chance to actually enjoy a new take.