Alright, I know "different strokes, different folks" is a thing that exists, but the claim that Blizzard sucks at everything...that really isn't born out by any objective look.
I mean, leaving aside any personal thoughts, let's look at some objective facts:
-Warcraft: One of the most successful RTS series of all time, especially Warcraft III, which by itself gave rise to the ARTS genre. Look up any list of top RTS games, and you'll see WC3 there somewhere.
-StarCraft: THE most successful RTS series of all time that single-handledly kickstarted the e-sports scene in South Korea, not to mention that SC more or less pioneered its style of sequential campaign storytelling and asymetric factions. SC1 is still played professionally to this day for a reason, and SC2 is in similar company. Similarly to WC3, look up any list of top RTS games, and you'll see SC1 and/or 2 on said list guaranteed.
-Diablo: Practically invented the ARPG genre. D2 built off that, D3 is one of the best-selling games in history. There's a reason why even close to 20 years after its release, you could still find D2 on store shelves (and SC1 and WC3 for that matter).
-World of Warcraft: The most successful MMORPG in history, period. This isn't a statement of subjective quality, this is fact by any metric, including sales, subscriber base, and the influence it had on the genre.
-Hearthstone: One of the most popular, if not THE most popular electronic card games on the market right now.
-Heroes of the Storm: Actually a bit of a blip, but still, one of the most successful MOBAs ever released. It never reached the likes of LoL or Dota 2 in popularity, but it still carved out a niche for itself, and is still going today, albeit in maintenance mode.
-Overwatch: One of the most popular and most successful hero shooters ever, both in terms of sales, pop cultural influence, genre influence, etc.
Again, this is me leaving out any personal thoughts on the matter - no-one's obliged to like any of the games I just mentioned, but to say all of that is garbage...well, that's a pretty big statement. It sort of reminds me of the contrast between "I don't like Sonic games" (perfectly reasonable) vs. "Sonic was never good" (um...). If we assume Blizzard "sucks at everything," then there's presumably a reason why everything I listed was as successful as it was despite the "suckiness."