I think getting an FDX1 before the Dusk spoiled my impressions with the Dusk, they both have similar resolution with the Dusk having noticeably better imaging and dynamics.
Maybe I was expecting a bit too much given that most people have gushed over the Dusk and is considered to be the ultimate sub $500 IEM
I personally care about that last bit of performance which means the answer to an upgrade is a yes.
BTW, Meze Advar is an interesting pickup, very few people own a set, I think the price + Meze's no-so-good IEM track record are the two big reasons why.
I auditioned an Advar for about 30 min, and also thought the lower treble is quite harsh. But for a single DD, it actually has very good resolution that can rival some midFI multi driver types in technicalities. The price is a bit off-putting though, huge diminishing returns abound. But to chase that last few bits of improvement, yeah you gotta pay for those marginal gains.