Sure! Just as a preface, I still also buy and build Lego sets, and in some ways, they’ve definitely become way better. Sooo many cool pieces and building techniques nowadays! It’s not like I’ve sworn off Lego or something. But after trying out competitors, the flaws are just becoming more apparent.

My main gripes with Lego’s development at the moment are:

• Piece quality has in general been deteriorating. Some colors have become inconsistent from one piece to the next, leading to an ugly patchwork of shades on what should be unicolor surfaces. Transparent pieces have become much less clear in a lot of cases, and are often scratched up out of the box. Some pieces (especially smaller pieces) have started showing very big and ugly mold marks in visible places. Some of this might be acceptable for kids toys, but absolutely not for the high-value display model stuff they’re going for so heavily at the moment.
• Printing/Stickers: Usually way too many stickers that you’ll mess up while applying, and will be destroyed after a couple of years. And in the instances where they do actually print pieces, the print is only one layer, which just looks really crappy when they’re trying to match the color of other non-printed surfaces.
• Set design: Lego nowadays really likes to put the craziest colors inside of models that have no reason for being there. This goes completely against what Lego originally stood for, as it makes it way harder to take a model apart and build something new from it that’s decent looking if you don’t have a bigger collection already. And oftentimes it’s not even completely hidden, just looking at a set from the wrong angle will sometimes start revealing the rainbow vomit.
• Instructions: I had quite a few errors in instructions over the last years, feel like that’s increased. Also, I’m not a fan of the extremely simple, slow-paced instructions from today, but that’s mostly preference and not a quality thing. They’re just going for the lowest common denominator.
• And then there’s also their behavior as a business - at least here in Germany, they’re doing some really shady things to try and bully competitors off the market.

Again, Lego is still, for the most part, far from being bad. But it’s definitely not the quality leader it wants to see itself as anymore, and for what you’re getting, compared to what you can get with competitors, it’s horrendously overpriced in my opinion. It’s still the most well rounded and consistent offering there is, though. It’s not the best quality, but you mostly know what you’re getting and there’s something for everybody in their lineup, whereas with other brands they’re often more specialized and have a much narrower catalogue. Oh, and also - minifigs. If the Lego-style minifigs are important to you (and as a brickfilmer, they definitely are for me), Lego is basically your only option, unless you want to go for expensive customs.