I'm going to be that guy, but MTX in non f2p games. I'm talking about paying money to buy extra resources, x2 exp, p2w maybe opening a lootbox for progression etc. MTX themselves aren't inherently bad but the avaricious AAA publishers has distilled it into something absolutely insidious. Sure its optional, but they are tweaking game settings/numbers so that it could justify their existence, you know; manufacturing a problem so they could sell you a solution. Either accept the grind (adding needless tedium to a game) or pay to get around it.
I'm sitting on the fence on continuous DLC. Namely RTS games. On the one hand, i should look at the DLC after i've beaten the base game and should consider if i want more. Plus its a good way to add the features that the Devs didn't have time to implement or add extra content to make it better.
Yet at the same time, it feels like constantly bleeding players for money especially if its additional features/content that enhances the base game. Again, this varies in implementation, sometimes the Devs retroactively add basic features (cities skylines) and a more complete feature is DLC. yet on the other-hand there's Gladius, there are only 4 factions and DLC for extra units etc. yet at the same time, i know that i'll probably not play the game after playing a single faction so i shouldn't worry. But when i had the chance to play the game i felt that the game was a really lightweight experience.
edit: i'll quickly add another one. A large world map with absolutely nothing in them. I'm talking about large fields or vast patches of scenary with nothing to do in them. yes, i'm not expecting every inch to be activities, but still if you don't give me compelling reasons to go there, its just pointless for me being there. it also makes large areas bland. And no, adding collectibles and fetch quests in those areas don't count. i think Assassin's creed / just cause 2 does a good job of just having loads of bases for you to see and do. Whereas Arkham knight's gotham was just visually small and also void of much content. It didn't feel like a city undersiege by spec ops or criminals. It was so piecemeal how they introduced everything.