The pace of the 'old time' RTS games such as TA and C&C Red Alert were like this. You'd spend a long time building up an army near your base and then just send them in to destroy the enemy in a single bitter battle to the death. Managing the battle would involve you grouping a load of similar units together and making them move together. It seemed that units were expendable, you didn't care as they never changed during the battle. A frontline would be supported by you sending more units in single file or small groups from your base...
I've played two 'modern' RTS games recently; there's the "LoTR: Battle for Middle Earth" and "Dawn of War" (which I bought yesterday), both of which have completely changed my perspective of how an RTS should be played. Gone are groups of single units and in their place you're presented with 'squads' or 'battalions'. In the LoTR game these gain experience and become better fighters because of it, this doesn't seem to happen in Dawn of War though.
But by far the best feature of both is the ability to tailor your basic squads depending on how they'd be used. In LoTR you can merge basic groups of troops together, choosing to create a multi-purpose squad. In DoW, you can tailor the squads with different weapons; effectively giving you the same sort of customisation. Using the same set of basic troops you can create a general purpose squad, or a more specialised long-range or close combat fighting group. I also like the ability to upgrade squads individually. LoTR lets you add upgrade armour, arrow type and the strength of the blades; DoW lets you add commanders, frag grenades and more. LoTR has banner carriers to boost 'leadership' and allow the squad to regenerate over time; DoW has sargents to help rally troops and features the ability to reinforce the squad on request (and a small cost).
I've found that this sort of customisation 'wills' you into playing the game differently. You begin to care for your troops. I've you've had a squad in place for a while, you don't want them to die and will reinforce their numbers and upgrade them if they weaken. I've also found myself playing more tactically; the modern RTS restricts the number of units you can create quite severely so you're forced to create customised squads and advance slowly in the game. Instead of massing a huge army and sending them all to the other side of the map you find yourself advancing cautiously, moving small pockets of forces forward and providing cover for the others, whilst all the while being prepared to drop back to a 'safe' area. You seem to use the units better; the long range units will be useful up front if the enemy is far off, but you must drop the long rangers back to provide covering fire whilst you send in your grunts to tackle the enemy head-on. I like the way squads can be broken up in combat - from the horse charges in LoTR to the huge explosions in DoW - it really does feel like war.
Suffice to say, the modern RTS game seems to put more of an emphasis on tactics and squad-based combat. Gone is the huge build up before a huge and final battle and in its place is a slower-paced game that forces you to think about where you're going to attack and how. We're talking about many minor battles that cumulate in a final, bigger battle. Altogether it seems better, more exciting and more immersing.
I like it :)