I don't know why unit pathing is so difficult in a lot of RTS games. In Rise of Nations, it appears to be particularly bad.
Oftentimes, even when there's nothing in the way, units seem to take circuitous routes to their destination. If I tell a unit to move directly to the left, for example, it will veer up a bit, then back down, or down, then back up, even though there are no obstacles in the way. Why is it so difficult to get units to move in a straight line? Is it really that difficult to have a unit's (x,y) position change in the direction of the vector from the unit's current location to the unit's desired location? I can understand if there are obstacles in the way, but this is on wide open plains. For me, this makes it *very* difficult to test their actual movement speed, because they won't actually move in a straight line.
Additionally, the whole "guys" thing (how a slinger unit is made up of 3 individual guys, each with their own pathing) means that the subunits tend to disperse as they move, so when you issue a new move order, they tend to try to get back together first rather than each moving to the new destination from their current location. This is very unhelpful if, for example, you are trying to get away from the enemy (the guys that are already away from the enemy will move back into the fray to join the guy that is still in the thick of things) or otherwise trying to move them efficiently from one point to another.
An additional note is that the units seem to periodically stop briefly before continuing every so often. It seems like this is at fixed intervals, i.e. every 128 frames or so. For most of the infantry this is not particularly noticeable, but the Modern Age Infantry and Information Age Assault Infantry do this thing where they sit down for like 20% of the time. This can be stopped if you re-command the unit to move again whenever they do this (i.e. the unit will, on average, move faster if you keep telling them to move, because it cuts out this periodic pausing thing if they're in the middle of it) but this, of course, adds to the micro when Rise of Nations is supposed to be a macro-oriented game. Maybe the developers were going for realism or something, but why did they think this type of "feature" would improve gameplay?