i mostly agree with @Heavy on this subject. as i’ve stated before when this subject has come up, i like the ability to fully respec in poe, and i like that it has a significant cost. for those who don’t know: to change your ascendency in poe, you need 5 respec points for each ascendancy node (40 points for a character with all 8 points allocated), and you have to run the lab again to choose your new mastery. (the usual method is to run the lab, then unspec all your ascendancy points in the reward room, then access the altar which now allows you to select a new ascendancy.) this, to me, is a suitably steep cost for fundamentally changing your character. you can’t do it by accident. only experienced players would ever go to this much trouble, and would know well enough to have gear and skill gems prepared for their switch. trading makes this process less painful, but still costly.
with LE in its current state, there’s no analogous way to implement a mastery respec system. respecing only costs gold, which is trivial for anyone who’s played a character into endgame (and hasn’t wasted it on gambling), and the points in the mastery trees are not distinct from base-class passives. there’s also no trading (yet) to soften the blow by making acquiring new gear easier.
i only see a couple of ways to give a significant cost to a mastery respec given these facts: one would be to massively raise the cost of respec’ing points in the mastery trees, which would be punitive to players who just want to change a few points around (since gold acquisition is fairly trivial, this isn’t the worst idea, but still a bit annoying) and wouldn’t address the issue brought up in the OP of a new player realizing that they chose something they don’t like.
the other would be something like what @Shtrak suggested, where the cost of choosing a different mastery isn’t monetary but rather that of player time. this seems like a horrible idea to me. we already have something similar to this with skill respecs, and many players have complained about it. if the same method was used for character levels, i think it would alienate a lot more people than the skill respec system has. (for the record, i think skill respecs are generally in a good place and feel much better now than when the only choice for choosing a new skill was to start over from level 1.) furthermore, what are you supposed to do with your newly hobbled character after losing those 20-30 levels? go back and grind story content at a much lower level? isn’t that exactly the thing people who want a mastery respec don’t want to do?
i think it’s worth considering that harsh learning experiences can be very good for a game. it may turn some people off and lose a few players, but it can also be the trait that people love and celebrate about it. the dark souls games are a perfect example. i’ve tried to play them, didn’t like them, and haven’t felt the urge to try them again. but they are extremely popular and the series has sold 27 million copies, so clearly i’m in the minority. it’s fine for a game not to appeal to someone for what’s perceived as a harsh learning curve.
when i first played poe, i didn’t look up any build guides. i took what i knew about hack’n’slash games, picked a class that seemed interesting, and struggled through the massive skill tree and gems system. i don’t think i got past level 40 with that character. i tried again. i failed again, but i got that character further along (i “fail(ed) better” in the words of samuel beckett). i played the game like that for a while before deciding i needed some help making a build that didn’t suck. i struggled to get the gear recommended by guides, i made do with what i could find, and eventually got a character all the way through all three difficulties (this was a long time ago). it felt like a major victory. i kept playing for a while, but at some point, i got burned out on the game and put it down for a year or so. i came back for abyss league (about 3 years ago) and re-discovered my love for the game. i’m nearing 4000 hours in the game by now, and have spent at least a couple thousand dollars on supporter packs over the years. the point of this story being: i struggled a lot with the game at first, found it engaging enough to keep trying, and even after experiencing burn out, came back and continued to play and spend money on the game for years.