I'm not a blaster, but pretty concentrated retired guy. Sunday night, finally coming up for air. I would say I have put in between 8 to 10 hours a day Friday, Saturday, and Sunday. Finished the night just leveled at 58 now. The end game grind will be pretty good, I'm thinking. Lots of variety, lots of mobs to crush, and loot to check and break. And a few different systems to get into and understand. Not as many as Path of Exile, but there is more variation than D3 or D2.
The use of both skills and the paragon board looks like it will synergize nicely. You will need to either work out how to put your points in, to save gold on respec, or follow a guide. It might seem a little like cheating, but trust me, it is just another tool to get into the game without getting too frustrated. There are a number of sites to chose from, I like maxroll.gg but ymmv.
For those who wish to enjoy a casual game, it works on that level too though. I found the story to be just fine, but I have been a Diablo player since it first release. So my bar is set pretty low. In fact, I played the whole story through on World Tier 1, and I didn't feel like I was behind on leveling at all.
At the slow rate I am leveling I expect that level 100 will be a while yet. Even before Season 1 releases I will get more hours than dollars spent. And then, I expect that I will try each class through the following 4 season, getting at least 75 to 80 hours minimum per season.
As for the gold, it gradually builds. For the bulk of the story mode I just crushed everything for mats for crafting. Once I started in World Tier 3 the gold got a little better. Try not to spend any money on vendors, and only imprint the most important aspects for your build. Once you build up a good amount of crafting mats you can start to sell some of the rare 2h weapons for 10k - 20k each. I hope that gold drops are a bit higher in Tier 4, but that is a few days away I think.
Overall, if you like the genre, I think you will like what they have put together in Diablo 4. It is dark, gruesome in some parts, like slasher movie gory at times, but then people asked for it to be more D1 and D2 with blood and guts!