Disclaimer - some of the stuff I've mentioned "down below" became a bit less "unpopular" with recent years, but still consider them as relatively unpopular.
1.Heroes IV was a step in good way (in terms of mechanics, not bugs at the release date :P) - it brought many nice changes (like participation of heroes in the battle, prisons, caravans), some corrections (creatures are coming day by day, not only every week, magic based characters are still important, but due to various magic schools hero needs to learn there are no more "bloated" magic heroes devastating everything with magic) but with containing the main character of the game - simplified economy, "two sides" tactic battles, a lot of exploration and gaining experience by heroes etc.
2.Diablo series is overrated. I personally can tell that I only liked the first game, which despite it's simplified mechanics (series of dungeons with very few quests to do) at least entertained me a bit and brought some interesting elements of plot and memorable characters
SPOILERS
( tragedy of King Leoric, betrayal of Lasarus, Lachdanan etc).
END OF SPOILERS
Sequel made me completely bored in about half of game, and I didn't even tried Diablo 3. I personally think that Warcraft and Starcraft series (not counting WoW and some weird spin-offs with Star/War characters) have much more to offer in almost every aspect. Truth is that both are different genre than Diablo, but still, as games they're in my opinion far more entertaining.
3.I'm extremely annoyed with the fact how much praises are receiving most famous nintendo game series (all this Mario/Zelda/whatever stuff) and generally Nintendo's stuff as well. I've played in some of their games (mostly on handhelds) and I could swear, that identical games (similar genres, content etc) but without Mario or Link wouldn't caught anybody's attention, but a bunch of indie-games fans, who don't have a problems with looking for interesting stuff to play. Similar thing with plenty of indie games, which were in last years released on Switch and suddenly "oh, how great they are" - written by people ignoring fact of releases on other platforms (especially PC). Plus overrated "beneficial influence" of Nintendo on gaming at all (especially historical, but not only). Bleh.
4. This one may be (probably) the most controversial - I've got sad impression that as gamers (at all) we're not totally fair when it comes to diagnosis some inappropiate content in video games. Almost all negative opinions are usually ignored or ridiculed. Of course I'm not telling that there is no unjustified "bashing" on other side - clearly some alarmistic publications about bad influence of video games are written without good knowledge of topic and made it on purpose in "alarmistic" tone.
BUT there are some information or publication which are presenting some problems in fair way, yet they're threatened in identical way. Like some disturbing content of some games in terms of presentic, let's say, "diabolic" themes. Yes, I know that Diablo is game about fighting with demon-like Diablo and his minions, but why then we've got so much in interface and icons stuff like pentagrams, devil holding health meter (what is it supposed to mean, and why in Diablo II it's in opposite?) etc? Or first Blood - quite the same thing, but more also in "game itself" plus making fun of desacrating bodies (kicking decapitated heads like ball + Caleb's comments). I can't agree that such content is not disturbing or that it's totally fine (even if concept of the game is showing someone who is rather "anti-hero" or villain, like Caleb) - I know about "freedom of creativity", but since games are part of culture, shouldn't we use there also some boundaries, limits? I don't see any type of discussion about such stuff in gamer's environment, which is a shame, because very often I feel like I'm belonging to two hostile "camps", where both sides are fighting each other and not trying to analyse anything or discuss with arguments.
5.This one maybe is not especially "unpopular", but rather "rare" - I've got an impression (and I'm sad with it) that we're recently having very few solid games from strategy genre - especially RTS (it's probably one of the rarest genre made by indie developers and "big guys" are also not taking too often this type on their table - plus those few games released in last years weren't especially good - such as Dawn of War III). But it's also the case for turn-based strategies, because most "turn-based" games are rather some tactic titles, not strategic, or mixed turn-based tactic with some different genre (sometimes aside from turns, it has nothing to do with tactic or strategy game at all). And cherry on top - lack of hot-seat game in many turn-based strategies nowadays. I always liked the fact that I can show someone (and play with someone) in the game with buying only one copy of game, plus it has some "social value" that we're meeting directly. Yet nowadays it's becaming quite rare - or having some extremely annoying "variations", such as "faked" hot-seat for WH40k: Armageddon or WH40k: Sanctus Reach).
