I think that one of the most disappointing things about D4 is that it actively punishes you for wanting to try new things via high respec costs and gearing/aspect requirements. This is especially true at end game because there is no "Refund All" for paragon boards. Hence why (accurate) build guides are so important.

Another thing that makes theorycrafting difficult yourself is that due to all skills being %age based, it's much harder to plan out the math behind a build.

Finally, while it's relatively easy to try out different builds while you're leveling, the landscape of what is viable when you hit WT3/WT4 completely changes as Glyphs start generating more of your DPS/survivability than the skills in your previous build, which dramatically changes what your build may look like. This change at end-game is great for variety (leveling builds are different to end-game builds), but due to the aforementioned way that D4 punishes you for wanting to try new things, it makes it pretty difficult in WT4+ to play anything but the "meta" builds.

All that being said, the Dev update tomorrow mentioned that they'll be going over Season 1 details as well as a bunch of QoL changes that are upcoming. So my fingers are crossed for at least a "Refund all" for paragon boards, if not multiple "Spec"/Armory slots.

Whirlwind Barb has been fun (trying to maximize spin uptime while unloading tons of damage), but optimizing it and maximizing the fun is way too dependent on a ring drop that I have yet to find (Bold Chieftan).

The best place for this type of content was, sadly, the Diablo4 subreddit. Something is also on YouTube but you'd have to dredge through hundreds of clickbait cringe videos to find anything worthwhile.

I think it's hard to find "professional" reviews discussing gameplay/classes in depth because the game leaves almost no room for experimentation and people just gravitate towards the meta builds. As an ice shard sorc main I'd love to form my own opinion on fire or lightning builds as well, but at level 60 it already seems like too much of a hassle to respec everything just to try something out.

They should either address the severe balance issues between supposedly viable builds or at least give players the tools to figure the alternatives out for themselves through experimenting.

I started sorcerer and beat the campaign. I felt fairly good but constantly felt like something was off. I think a melee ranged sorc is really cool but it should be an edge case. It felt bad because I went into it picking sorc to do the opposite. And all the net builds are just all 3 defense skills with a different core skill.

I started Rogue soon after and the builds felt infinitely more dynamic. Imbuement melee or ranged. Traps? It’s just so much better.

I’ve taken my Druid through to WT3 and ran into the same issue with bear a couple of times. I’ve respecced to a companion/tornado build now however and everything except Nightmare Dungeons is a cakewalk. It’s a nice mix of powerful cooldowns and spamming storm strike/tornado.