As much as I like NetHack (and I really do), it honestly does have a number of widely-acknowledged and somewhat serious shortcomings. Among other things: the chance-to-hit formula is so broken that it causes entire _categories_ of features (such as shields and two-handed weapons) to go mostly unused; Elbereth was severely unbalanced in 3.4.3 (the new version takes several measures to try to fix this -- it remains to be seen if they will be enough, I suspect not); spellcasting roles generally have to spend the first third of the game playing as handicapped melee combat enthusiasts, which is not as intended; the status area of the UI needs some serious improvements -- not least, it should be easier to notice when your hitpoints are getting low; if the Unicode support is good, that'll be news to me (I haven't had time to really look at the new version yet since the release -- the leaked version a year or so ago had preliminary Unicode support that needed help); the score formula is so broken that experienced players almost universally ignore score completely (both major tournaments focus on other things), and getting a _low_ score is substantially more challenging than getting a high one -- which would be one thing if the score system were designed that way, like golf, but it isn't; the last 50% or so of the game in terms of how long it takes you to complete it has the last 2% or so of the plot and interest and anything that matters, leading to situations where players get bogged down and don't play for weeks at a time because they have completed the interesting parts (up through the Castle) but aren't yet close to winning in terms of time investment -- this happens to a _lot_ of players, perhaps the majority of players who are sufficiently experienced to win the game repeatedly. Also, 3.4.3 had a number of rather serious bugs, including a number of crash bugs. Most of those are fixed in the new version. That's a good thing.
There's a reason the variant community is so active, with new variants popping up every few months. People keep seeing things that need to be _fixed_.