Well, you're assuming quite a bit there darvin... one jump away lay a sizeable force of assailants, the advent player knew that and realized he was being baited.
The way you stated it, I think my presumptions were quite fair. You made no indication that there were any other factors in play other than the two fleets you described. As I already stated, the assailants were what the Vasari needed in this case to tilt the scales, so their presence does indeed give Vasari advantage, but you had to specify that.
Just because a unit isn't fielded doesn't mean the player doesn't have it.
But it can mean that this unit is not available in the coming battle, which is significant. This isn't Warcraft or Starcraft where worst-case scenario you can get a unit to cross the entire map in about a minute. It may take five to ten minutes go from point A to point B even on a moderate-sized map
The guardians were the first thing to be taken out by the sc.
Then the Advent player wasn't particularly competent. Guardians take reduced damage from both types of SC (fighter and bomber), and the Advent had both a Progenitor and Halcyon on the field. He shouldn't have been losing guardians to strike-craft alone, much less early in the battle. Now, if you had maxed out phase missile research I might believe it (since this would realistically allow you to kill the guardians in spite of shield restore) since the Advent lacked much in the way of flak and fighter support of his own. However, if you had any less than 20% bypass chance I don't see the guardians dying so long as the progenitor can shield restore.
You assume that the guardians had repulse; the player was attacked just as he was trying to research repulse.
The guy has dominas, which means he had all the prerequisites necessary for repulse. If he had five labs, lots of guardians, and an illum-based army I can't think of any good reason not to research repulse. Frankly if he was competent, he'd already have this ability on the field.
5 subverters was enough to deal with the guardians; in this case a 20 second window was enough to take them out (granted 25sec later there's only one subverter left.)
Five subverters against six guardians? I will say that Vasari definitely have the opportunity here to outmicro the Advent and get a win that way, but the way it falls there are more guardians than subverters. You have to wait for the 20 second cooldown to expire before you disable the sixth guardian, by which point (I'm sure we can both agree) you're lucky if you have more than one or two subverter left. You might get a window of opportunity out of it, but I doubt repulse would be down for a period greater than ten seconds.
the vasari player could rely on having full AM whereas the advent player would have (nearly) empty reserves for the caps when they jumped in
Dude, that's HUGE. That completely changes my analysis. Frankly I think the Advent was foolish to engage in this situation, as he'd have had a fair fighting chance at full strength, but with minimal antimatter reserves you just have to wait for him to burn through what little is left.
The big thing here was that I was presuming the Halcyon was equipped to deal with the strike craft. It's very obvious that this Advent fleet has little in the way to combat SC and relies on telekinetic push. Running out of antimatter would be a death sentence to them.
people don't use the z-axis nearly; enough; it is a critical potential force multiplier.
A lot of people consider z-axis control abusive because of potential exploits. For instance, the TEC starbase has blindspots directly above and below it, and that's cheese, plain and simple.
Based on the information provided, I wouldn't give the original poster advice to try to chase down bomber carriers with HC's -- bombers are the hard counter.
Bombers are a counter to HC, not a hard counter. Compare flaks against fighters to bombers against heavy cruisers and you'll see what I mean. Generally it's viewed that two flak per (TEC/Vasari) carrier is a sufficient bare-minimum coverage. That's a counter ratio of about 4:7. A similar ratio for heavy cruisers to carriers would be 2 carrier to every 5 heavy cruisers. I'm sure we can agree that this will not cut it, which is why the bomber vs heavy cruiser counter is considered catagorically different from "hard counters" like flak vs fighter.