the SC2 campaign is still fun and i replay them, but you can tell when different teams were involved as the playstyles are wildly different
The Terran campaign was all about slow long missions, with brutal difficulty needing one unit mastered to succeed (the one introduced that mission, effectively forcing you to train with it on that difficulty)
The zerg campaign went faster paced, and increased the speed of MP at the same time. Quicker starts, more action, shorter missions (and one heck of a good story, tbh)
Then came a long stretch of nothing but focus on the top-tier Esports players with balance fixes screwing over casual players massively - this was the worst time to play the game, because anyone could master certain basic things (cannon rush/zerg rush) and the effort to stop these things required far more control and APM than using them, screwing up the balance with 'cheese' being the only way to advance to a certain level in the rankings (then being useless past that point)
Then the final protoss campaign came along and it felt like a shift to CNC Generals: Zero hour mixed with WC3, heavy focus on multiple heroes, the ability to swap units out pre-mission, toolbar superpowers.
These were beginner friendly, and higher skill with them just let you have more FUN with the units. I can still replay this and try different combos (ex: sentry units that regen shields for friendlies, or 50% more damage - but there are other options for shield regen out of combat, so you can turtle with combining them, balance things out, or go full aggressive)
Noval DLC came out in two small pieces and while the second half is extremely fun, the first half was rather... lackluster. It felt almost console down-sized with very small compact single unit based missions for no reason. Even in the large ones, you'd suddenly be dealing with a single unit (Nova) for the last 10 minutes in an entirely different style of gameplay for no reason.
At some point the coop guys got their ball rolling mixing the best of the campaigns (the very different playstyles) - one that's only got 5 over powered heroes, one thats all about cheap massive armies of weaklings that can be replaced in seconds, one that has a giant frikkin laser beam that does the murder for you long distance - all the fun options, and each one having options to let you spice them up (prestige ranks that would say, double that lasers damage but double the cost of units)
And i've never seen anything as fun. Those devs were making an RTS coop game StormGate and i hope they get it right - half of what worked for SC2's coop was already knowing the heroes/units from SC lore, so i hope they can surpass that handicap (In coop, it helps to instantly know your allies abilities and weaknesses on sight)
StarCraft 2's veterans left Blizzard to make Stormgate, the co-op RTS of their dreams | PC Gamer
Unfortunately it sounds like they're only doing the narrow hero based version, another DOTA or Heroes of the storm - and that holds zero appeal to me.
AOE alternatively is extremely slow paced with the decisive combat happening really fast - which just encourages the situation of a lot of hard work, and the opponent quitting if they're losing or watching a long drawn out death for yourself you can never recover from
This is hard to say if they mean a massive army style game or a singular unit type of game - it may be context not delivered in the quote
SC2 coop dealt with this with the commander powers, allowing you to focus an army in one location and back up your ally with the abilities, without the god-tier APM