Couple of comments:
Looking at that screenshot... is that really what the units look like? Nothing was moving and it took me several seconds to figure out which unit was which (I think... anti-air has one black rectangle/barrel and the others have 2?). That's kinda sad.
The anti-ground tanks are on the right, the anti-air tank on the left.
I've rarely had a problem with SC1's pathfinding. There are easy ways around it, such as group up before attacking, multiple groups, or simply give them short paths.
Though in a game like Archon, you sort of want to have good pathfinding.
Because you're going to be giving single move commands to a single unit at -3:59 (the very edge of the Alterable Past) and want all of the units under its command to get to the destination correctly.
In any case, I've been enjoying it. There are four (?) campaigns (based on the achievements steam lists) and I've just started the second one. The first campaign teaches you how to play the humans, the second campaign teaches you how to play the vecnir (the biped race in yellow you see throughout the first campaign). I assume the third and fourth likewise teach you about the other races as well. There's only one story, as far as I can tell, but that each campaign only sees one side of it.
Unit differentiation is, however, badly needed. You can't even always rely on double-clicking to select all units of the same type (you also can't ctrl double-click to add a unit type to a selection). Along with the "the selected unit stats" needing to be listed (the "this unit does this much damage to air/ground" stats are only show as a tool-tip to the Build Unit button).
Also, despite the time travel, you can seriously fuck up hard. There's one mission in campaign 1 (either 7, 8, or 9th) that I had to start over from the beginning seven or eight times simply because the Thing I Didn't Do, but Needed To was always 5 or more minutes in the past. When I did finally win, I think on average I was looking at -3 minutes, queuing up more units and sending them towards the front lines so that they'd
arrive when and where they were critically needed (and then I'd have to micro combat at about -1 minute, then head back to -3 or -4 to queue up more units to send present-ward).
The AI is terrible, however. The enemy AIs that control units, even when they can move back and forth in time like I can, aren't a challenge. A friend and I played the one 2v2 (there's ONE 2v2 map and ONE 3v3 and ZERO 4v4 maps) against two computer players. He steam rolled them at about 6 minutes in. Both of them, by himself. Took until about 14 before we declared victory, as the game though there was still a unit around somewhere that might be able to pull the game around (probably one of those "didn't fall into the unplayable past" things).
We then faced off against each other, and despite being down most of the game I won, and won hands down. He'd attacked my base several times, but I always managed to make it a tie, at worst (for myself), then I took out his resource outposts and built up my own army (mostly flying units against his mostly ground) and using a contingent of ground units (I left sitting on his northern ex-resource facility) as a distraction, I flew my main force around south and attacked from both sides. Oh, and all of this was at about -2:30, making it fall into the Unplayable Past rather rapidly (I think we peaked out at -3 as editable*).
Oh, response to a question of sending a unit forward in time:
Yes, you CAN do that. It's not useful.
*The time at which the timeline enters the unplayable past (with full chrono energy) is seemingly random. I think it's editable somewhere for multiplayer games, but I've noticed that in campaign maps it ranges from -3:00 to -6:00 for no apparent reason.