If by visual progression you mean corresponding to the strength of your character? I'm gonna say it's pretty much non-existent. You'll have access to all your classes transmogs fairly quick. You can look good at level 10. There is MTX but none of it is tempting to buy in my opinion, as the in-game transmog is solid.

Path of Exile has been a live service game updating for 10+ years. It shits on D4 in terms of content, diversity, and gameplay. Path of Exile is in the best state its been in for a very long time with a plethora of very viable builds available for every class and for every bit of content in the game - and there is a TON of content. If you can stomach a steep learning curve, Path of Exile dominates the ARPG market on every front except maybe graphically. There is also no visual progression in Path of Exile. You're gonna look like a clown unless you buy MTX. Straight up. It's awful. They actually havent even finished the 3D art for a lot of the gear in the game still.

Where D4 shines relative to other ARPGs on the market, imo, is in its simplicity coupled with very nice visuals and just fantastic sound design. It's also a lot of fun with friends. The skills all look good and feel good and there is a lot of attention to detail graphically that makes the game shine. You'll get a hundred hours or so of fun, and with each season (which there are no details of currently) there will be more and more to enjoy. It is barebones at the moment.

I've played PoE for 3000 hours over the past 10 years and I've put at least a hundred into D4 since launch. If you want to get D4, I'd say go for it. You'll get your moneys worth. It's fun, simple, and looks good. I'd also suggest Path of Exile too! Sorry I can't speak to Necro for ya but I hope I helped and answered some questions you may have had about the game.