My players never use combat rules

If there is one section of the rules that I see a lot of OSR authors blogging about and trying to find new ideas or solutions for it's combat rules. I think generally for the following two reasons: 

1.  The fighter in most OSR rulesets seems lackluster. Wizards have spells. Thieves skills. Fighters, just are good at well, fighting. 
2.  Combat in OSR rulesets tends to be abstracted. It can turn into a slog fest where both sides just trade blows until one side dies. 

 I know I've spent more than my fair share of time coming up or tweaking combat rules. In general most tweaks to combat rules tend to take two different approaches: 

1.  Improve the fighter: give the fighter the ability to preform signature moves that change what is being done beyond just trading blows. This could be something very specific like a fighter who has some kind of ability to trip enemies with their spear. To a more freeform 'maneuver' ability like Dungeon Crawl Classics mighty deeds where the player rolls a deed dice and if comes up a certain number they get to perform some kind of special maneuver in addition to their attack. 
2.  Improve the tools of the trade: grant special maneuvers to the weapons themselves where the fighter is an expert at using the tools of his trade and to make the weapons themselves more interesting. For example a pole-axe can attack from farther away, a mace reduces an enemies armour. 

While I do think these two ideas are not bad solutions. I find players still don't engage with them much. And you can absolutely forget about players using various 'modes' of combat. Such as fighting defensively where you get some kind of bonus to your defense at cost of your attack. I have played several editions of DnD and can maybe think of 1 or 2 occurrences where someone actually remembered these modes of combat, or specific combat maneuvers from the rulebook and used them. I'm glad that OSR seems to have largely done away with them. 

As for the solutions OSR rulesets tend to provide. For solution 1 I find players will use combat maneuvers only if the combat situation really prompts them. They tend to not think of them as signature moves and more just a response to the situation they are being presented. So, if you present them with a fight against a bandit they won't think of using a trip attack. However, if you present them with a situation where they are fighting a lumbering troll with long spindly legs, they are maybe more likely to think, hey if we trip this guy, the fight will go better. 

As for solution 2, I find players rarely engage in micromanaging their inventory or combat 'builds'. They tend to just pick a weapon and armour type, and stick with it. I think this is partly because most times you don't know what kind of things a dungeon is going to contain. Yes a mace may be better against armoured opponents, but if you don't know if your next combat encounter is going to contain heavily armoured opponents why bother bringing along the mace? I find players hate micromanaging their inventory. I know I hate it. Even if I have room for multiple weapons, I'm very unlikely to bring along extra ones just in case I come across that one enemy type it's good against. 

 I find the commonality between these two things is that combat in OSR style games tends to be very reactive. The players are simply reacting to what kind of combat encounter they are presented. If you don't present them with an interesting one they'll simply just default to trading blows until hopefully, as quickly as possible, one side is dead. If things go bad for them, then they'll just try to run away.

 Now, I do think it's very valuable to have some kind of general rule for combat maneuvers where the players know that yeah, they don't just have to attack, they can jump on the giants back or throw sand in the knights eyes or something. That there is an easy way to resolve such things. In my games I tend to use ability checks. 

 I also think it can be valuable to give a fighter some kind of defined combat 'theme'. Like, hey, your guy is from the mountains up north, he's really good at fighting giants, tripping them and jumping on them. Or your guy used to be a gladiator, he's good at fighting dirty. These kind of backgrounds or themes get players thinking about their characters and I think go further for them actually making up or using some kind of signature move than just giving them a mighty deed ability. 

 Additionally, I think one of the things about the fighter class that only really becomes apparent in play, is that if all the other characters are shit in combat by having low attack scores (as is the case in most OSR rulesets) the fighter really does stand out and feel empowering even if most of what their class is about is simply that their attack bonus increases +1 every level. IT doesn't seem flashy on paper, but I find in practice when the players do get into combat the fighters really shine and are the ones who are actually taking down enemies. I've gone back and forth on combat rules over my years of playing, adding, removing, tweaking, revising. In conclusion the only things I find that have really stuck are: 

1.  Make the fighter actually good at combat and the other classes shit. This is most commonly done by having the fighter be the only class whose attack bonus increases every level. If nothing else do this.
2.  Make sure everyone knows that they can respond to a combat situation in ways other than trading blows. Want to swing off a chandelier? Cool, you can. Want to jump on the giants back? Cool, you can do that too. 
3. Give the fighter a theme. Your fighter was a gladiator? Cool, He's really good at fighting dirty and throwing sand in people's eyes. Your fighter was a legionary? Cool, he's really good at using his tower sheild to protect others who fight alongside him. 
4. And probably most forgotten thing of all. If you want your combat to be interesting. Don't make more combat rules. Make your monsters and the combat situations your players find themselves in more interesting instead.