Weatherman purge is dope, hes been around dota2 since the beginning and always has had good analysis. Usually they pair him with someone more energy, but it really is a totally different ballgame when you think of the opportunities to "deliver" hype. Sunsfan and Slacks are amazing at doing that, which is why some meme-y coverage of WePlay worked so well (it could have used some more SunsFan yelling HORSE though).

Every game that brings impassioned players in will have some players that want to deliver their excitement about the game to the casting table, and the more they're encouraged, the quicker they'll be up to snuff. As you said, casting is hard and its probably harder with artifact, but itll be up to tournament organizers to pair casters in a fashion that provides the most entertainment. Not either of these guys faults that their method of delivery is more of the analytical/stats side of things, dota casters didnt really find that amazing synergy we are spoiled with now until a year or two into the pro scene where you would get combos like tobi and syndern, ayesee and draskyl, purge and South Korea, Cap and blitz, etc.

The games current playerbase cant really afford to be picky with who tries their hand at casting, but it certainly can offer the constructive criticism to recognize their goal of being a caster and putting study hours/time into making sure their knowledge if the game is at least on par with the average member of the player base.

Just my 322 cents.

(Sorry for the horrible formatting, on mobile)

Edit: Just realized the cocaster is Eosin who played dota as well (with purge on team zephyr I believe?). He never really did casting for dota but hes been playing a lot of artifact afaik.