The reason why I don't like Spring RTS engine much (or any other RTS apart from SupCom 2) is that they have a great open platform, but totally broken ass pathfinding. No flow dynamics in formations (no formation pathing at all) and so what happens is what I call the "wall of fire" problem..
You see, when you order 2 formations attack via move-attack each other only the first units fire and then stop which leaves the units behind those first ones in a bit of a problem, now they have to path AROUND the first line creating a wall of units that fires.. and then STOPS and finally, the units first stopped are now dead which means there is a huge hole and because a tight formation always wins in this case, the best tactic is to never attack if forces are even. Which is of course, totally stupid.
In reality, what I described is of course how a good broken pathfinding works, a totally broken pathfinding makes the units in row 2 stop entierly because no path resolves for the units in the center of a group. As you can tell, I don't much like games with broken pathfinding 
And supcom2 has the best. The absolute, completely, best pathfinding of any RTS ever made. And this is why I am actually a bit miffed supcom2 received so little mod support. Because that game is revolutionary in some ways, but it dies off without any POINT because GPG dropped it like a wet sack of rice (and the pathing feature with that)
Sidenote: It is a while since I tried Spring RTS, so should this issue have changed I'd like to know...
Well there's a few things I want to address here.
1. Total Annihilation is not like your typical RTS, you don't have to tell your units to "ATTACK" something. When an enemy comes in range, they automatically fire, unless they have the "hold fire" option toggled. So in order for your units to fire at the enemy, all they have to do is be in range of the enemy. Now there is a small bit of micromanagement involved by putting your fastest, closest range units in the front, and your slower, longer-range ones in the back, but that doesn't seem unreasonable at all. Once again "blobbing" is a bad design mechanic.
In Balanced Annihilation, you don't even have to physically see the enemy in order to fire at them! Units will shoot at radar blips if they are in range.
In other words, perhaps you didn't understand the way combat works in BA. You don't select your blob, press move-attack, then forget about them. You need to have at least a moderate amount of micromanagement (nothing major, just making sure every unit is in range, and the fragile units are in the back), which isn't a problem since the game automatically takes care of most of the macromanagement aspect for you. One of the things I've always loved about TA, is that unlike other strategies games (*COUGH* Starcraft), Total Annihilation WANTS you to be in the battle. It makes base management easy, and makes battle micromanagement complex enough that you need to be there to succeed, but simple enough that it's not overwhelming.
2. Supreme Commander 2's pathfinding was nice, but a bit unrealistic. (For anybody who doesn't know what we're talking about, here's the video:
http://www.youtube.com/watch?v=bovlsENv1g4). If your units are moving through each other, it makes sense that they move out of the way and stay in formation; but it is absolutely ridiculous and stupid that 2 formations of enemy units make a perfect hole for each other to move through, as if they've both agreed to politely let the other pass (while killing each other).
Secondly, SC2's formation system was very linear. The game made the formations for you and you couldn't change them. You couldn't choose whether the units move at group move or individual speed, so everything is ALWAYS in formation and ALWAYS moving at group speed. Can you imagine if AI War played like this? This was especially troubling when you have fast, mobile units grouped with Colossal, Experimental Units which move at the speed of molasses. The other big problem was that all the units had to be ordered to a specific location. This always really bothered me.
Spring RTS is the ONLY RTS engine that allows you to make your own quick and simple formations with the drag of a button. I swear to God, this system is so simple and intuitive, I can't believe nobody else has thought of it or used it. Simply by selecting your squad, and drawing a line on the screen, you choose how your formation ends up when you reach your location. With this command, you can easily make walls, Blitzkriegs, search patrols, squares, delta formations, or any formation you want instantly. I'll take this over the unrealistic "Flow Pathfinding" any day.
Here are some examples:
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Now tell me
THAT isn't cool. By the way, all the red drawing and lettered markers you saw were done IN-GAME. That's their in-game whiteboard system, which makes it easy to communicate and plan strategies with allies - another unique feature that no other RTS game has.
