I think why its really hard is because cloakies are bad at attrition, have inferior skirmishers to most.
Easiest factories you can get vs ai are cloakies (mirror) and tanks - because ai is bad at abusing their strengths and cannot swarm with expensive units and rockos are great against most of them.
Amph makes earlygame very hard due to duck vs glavie matchup Buoys also call for snipers because Archer is cheap fast riot that counters glavie swarms (snipe archer swarm buoy).
Jumpers make defending and counterraiding a hell because of pyros that always jump away and firewalkers later.
Shields should actually be on the easy side as well, but bandits are strong vs glavies, thuglaw is a problem and Felon calls for snipers.
Air - the ai seems to avoid air with just 2 factories - and it's bad with bombers anyways.
Hover - it's on the easy side as well - however halberds are hella annoying killing your defense and its hard to keep up attrition vs scalpel. Lance can be very annoying too.
Lveh - Scorchers fight even with glavies, Fencers make most porc useless unless u build Stingers and then you wait for Impaler. Overall quite easy matchup but you have to find and kill all impalers or say good bye to all porc. The most scary thing about lveh is the speed of their constructors.
Cloakies - all is good - scythers are annoying and hard to fix problem
With that said ai prefers to spread units to all places a little bie and that makes swarming their enemies with glavies easier even when the matchups are unfavorable.
Anyways the fact that it took me 7-8 attempts and Manu did it at 1st shows how big difference of a skill is there between us. Respect :)