Heyhey! Thank you so much for the thoughtful comment! You've pretty much hit a lot of the points that has been subject to a lot of thought and compromises, so as you said - the RPG elements are severely toned down in favour of a more rapid focused experience that mainly focuses around the core dice mechanics. Also, there's certainly always some kinks that need ironing out. In any case, I hope you keep experimenting with different relic builds - some of them alleviate some of the difficult parts you brought up (which are all completely valid - some classes are less suited for some situations, and some just feel less fun/rewarding than others depending on your playstyle). It's been a constant issue of giving classes power, without making them overpowered with the right relic combinations - and given the possible combinations that's been quite a challenge :). A class that felt weak with some combos, often turned out to be absolutely broken with others. So, in some cases I am sure some classes just feel downright worse - but we've tried to minimize those situations as much as possible.
Regarding the elementalist - if you want some spoilers: tethermage's helm and tome of wisdom can be pretty potent and carry you through most scenarios. Not to mention some of the end-game things (Wand of Inspiration) that keep refreshing abilities and gives you more longevity for longer scenarios (or Chaos Realm) :). That allows you to almost exclusively focus on gems, gold, and shields too so it has the benefit of stream-lining the dice a bit.
Money generation is also something that can be played around with in various builds (Necro has the sacrificial ritual, Chest Plate gives more chest reliability, Tithing and similar abilities - while semi-randomly accessed - gives lots of cash, Tethermage's Helm gives you protection so you can just "hide" and focus on gold, and some classes in general need to focus less on shields/gems so they can focus more on gold faces, etc.). Another way to alleviate it a bit is to actually stall out some waves to make use of more turns (increasing your opportunities to stack up on resources and pick up more gold upgrades as the store keeps getting renewed), and proactively use stun or defensive abilities to focus on coins rather than worrying about attacking.
But again - if those styles and strategies don't feel good, they just don't feel good. So your mileage may certainly vary!