It depends upon the context of play. Most RTS games will have some focus on timing and maneuvering multiple units and in multiplayer the importance of doing both proficiently cannot be overstated.
That said, there are a few general guidelines for games that meet that demand. First, the focus of the game cannot be on building an army during battle and second, the smaller the unit caps the better. With those in mind, here area few games and franchises that meet the request:
Ground Control: Ancient by modern standards. A bit of a rock paper scissors game but maneuver and timing are still important. Multiplayer is dead I'd assume but the campaign is of reasonable quality. Units are controlled by squad and there are a maximum of 8 squads in any given level. Special abilities are a limited resource so deploying them properly is key to success. The game is also notable for being the first game I can remember that had artillery that worked like real artillery - i.e. staggering range (generally it could hit anywhere on the map) and firepower. In multiplayer, it made the fog of war tremendously useful and was a key reason to have infantry or scout vehicles.
Total War: The single player campaign is divided into two phases - a turn based 4x strategy game of enormous depth and real time control over your armies in battle. You control squads of troops and the manpower you bring to a battle is all you'll get. There are various systems of reinforcement which handle things if you bring more than the maximum number of squads to any particular battle. Precise timing is never terribly important and combined with small unit counts battles tend to be rather relaxing affairs.
Company of Heroes: Like the previous two, this game focus on squads rather than individuals. That said, maneuver is incredibly important as is timing, especially in multiplayer. It is rare that any given battle will have you frantically pushing buttons and selecting troops and maneuvering them as the game is structures such that you probably won't have a huge army in a particular place at a time. The game does feature primitive tech trees and you do build an army as you play but the maximum army size is quite small - at most perhaps 20 units.
Dawn of War: Similar to the above in most ways, just less refined and featuring a different aestetic. The various expansions have lots of quality content in single player but I myself never cared for the multiplayer portion.
Dawn of War 2: Worthy of being noted separately as it is quite divergent from the first. The base campaign and the first expansion (Chaos Rising) gives you, in the end, six units of which four can be brought to a fight. There is no building of any sort beyond a limited stat progression and item collection system pursued between levels. In many ways, the campaign is incredibly weak as you don't really win through superior tactics or strategy so much as dogged persistence and tedious advance. The game's single player simply does not reward doing anything notable. Some micromanagement is important of course, largely in the form of directing special attacks. The last expansion, Retribution, features a minor base building mechanic (basically a simplified and accellerated version of what you find in the multiplayer) but the same qualifications as above hold. You win with crushing weight in firepower and nothing else. The design simply does not allow for bold or interesting maneuver. Multiplayer is a different story. There is a minor army building mechanic but even an end game army may be as few as 5 unique units (or as many as 12). Unlike the other games, this one is built around precisely executing commands, maneuver, and to an extent, simply selecting the right object to bring.
Of the pack, the first is probably off the list as I don't even know where you'd find it or if it runs on a modern system. Total War is readily available on steam and if you go that route, stick to the more modern games - anything from Rome forward. In a toss up between Dawn of War and CoH, I'd probably opt for Dawn of War personally - I simply prefer the aestetic and that game held my interest longer than CoH. Of all of them, I have the most experience with Dawn of War 2 and the various expansions and of them the most recent is probably the better choice. In total there is more single player to be had albiet spread across six different campaigns. The multiplayer is also more current which means it is often easier to find a game. That said, many people still favor the old expansion Chaos Rising out of concerns of balance or simply (as I came to in the end) hating Steamwerks with a passion.
