I have been playing the venerable old WRG 1925-1950 rules recently, using them for my recent solo Op Martlet mini-campaign.
The rules were written by Phil Barker and published in the early 1970s but still hold together reasonably well. The rules are meant to cover the span from reinforced platoon to company-level actions. Each turn represents about 30 seconds of activity. 1 model represents 1 real vehicle, an infantry base represent a c.4-man rifle team or a heavy weapons team. Two ground scales are suggested: 1":100m for big tank battles using 1:300 scale vehicles, 1mm:1m for other games, or those using 1:72 scale vehicles.
Command is done by very basic written orders given to each platoon element. The game uses an IGOUGO turn sequence but firing comes before movement - this neatly precludes the need for any 'overwatch' rules (the firing player can move any opposing elements to anywhere they could be seen in the preceding player's movement).
The rules for spotting, movement and firing are all relatively simple. Direct fire weapons test to hit - which effectively suppresses the target - and then test to destroy the target. It is a simple D6 roll with very few modifiers (easily committed to memory). Area fire weapons work in a similar area but use beaten zones and a broadbrush "hit anything in the open with a 5+, anything in cover on a 6" type rule. Spotting is done entirely by range (no dice rolls); it is difficult to spot concealed infantry and anti-tank weapons and so on! Combined with the fire-first turn sequence, this obviates some of the difficulties caused by the all-seeing general syndrome and restores some of the effectiveness of these troop types in comparison to tanks (which are often easier to spot).
Infantry is very hard to kill except at extremely short ranges. This seems more-or-less in line with historical reality. Machineguns are a lot more useful than rifles except at very close quarters and infantry attacks - even with superior numbers - are quite hard to sustain in the face of fire. They will normally degenerate into a sporadic exchange of fire (again, all quite realistic).
The system uses very simple armour classes but they all seem sensible. It doesn't give extensive equipment details and no orders of battle at all, so gamers have to do a tiny bit of homework to make sure they know what the weapons, armour class and speed of their vehicles will be (it takes five minutes, maximum). The rules only allow suppression and knock-out results, there are no intermediate stages of damage, which some gamers may find too simplistic.
Morale is considered by means of a reaction test. There are a number of situations where reaction tests must be taken and the chances of troops being halted and/or forced to retire to the nearest cover are reasonably high. There are a rather larger number of morale modifiers than firing modifiers, although I became reasonably familiar with them after the first couple of games.
The rules cover the use of smoke, field engineering, air support and weather. As befits a 1970s publication, there are no pictures of miniatures or even explanatory diagrams however the rules are tight enough to not require them.
Issues? Smoke provision is very generous (I suggest using the rules as given but halving the distance screened, seems to work okay; since I play solitaire I may not have stumbled on the most game-y uses of smoke. I like the infantry rules, although if playing using the 1":100m ground scale infantry movement will be very slow! Some gamers might find the lack of differentiation between a rifle team, an SMG team and an StG44 team problematic, or the lack of differentiation between a Bren and an MG34. My own collection is for Normandy 1944, but I suppose that having deployed infantry mainly defend static positions in the midst of armour battles might not be a too bad fit for the Western Desert, say. Again, I like the armour rules which I consider helpfully concentrate on the most fundamental details bit those looking for more tactical chrome may baulk at the simplifications, especially in the way damage is dealt with. Some gamers may be pleased with the here are the rules, you work out the equipment and the organisation whilst others may prefer the "handbook" approach of Flames of War/Games Workshop's Codex system. There are no special rules for specific equipment, tactics or "national characteristics" (with some marginal exceptions to the latter) which gamers may find very refreshing or a bit annoying. A search online will yield details of the "bazooka backblast" exploit...
But I highly recommend these rules to gamers who want a fundamentally sound set of WW2 rules, which are now available free and play smoothly and quickly. There are some examples of me using these rules here.