Having no inventory system just means you have less of an RPG
Speaking as someone who was a bit of a latecomer to RPGs, finally realising they were her real "comfort zone" sort of genre, I wasted too many years playing shooters that I found somehow unfulfilling. Not a criticism, just not really my cup of tea. Having spent years catching up and playing nothing but RPGs (or at least stuff with a significant overlap for the genre pedants, e.g. the Stalker series) it felt incredibly odd going back to a pure shooter and thinking "but where's my inventory?" Especially that confusion of simply running over a resource to pick it up. *shudder*
Though I suspect the OP's message isn't so much about having an inventory but how it's presented to the player, which can make all the difference. Talking of shuddering, Skyrim's was one of the worst I encountered: even with a fairly frugal amount of stuff, it was a pain to manage. User-made mods were slow to come about thanks to Bethsoft's inexplicable decision to make menus use Flash, but they ameliorated the awfulness a bit. It was still horrible, though. I guess it's subjective, at least to some degree; I rather liked Oblivion's with the Darnified UI added on, but it was quite easy to mod in all sorts of ways thanks to its much more sensible use of XML.
Still playing Kingdoms of Amalur at present, a game I really like but its inventory system is one of its weak points; especially trying to find stuff when crafting or selling, as a whole bunch of stuff is jumbled together and has no sort options. I guess subjective or not, that isn't the way to do it.
Overall, it's one of those things that really needs careful consideration as a quality-of-life thing. I'm somewhat reminded of my job as a sysadmin, where as a newbie I'd take offence at people demanding to know what it was I did because they couldn't really figure it out. As I got older and more scarred by various problems I began to realise that the hallmark of me doing a good job was that people didn't really notice the computer infrastructure, it was just a thing that did its job. It took a lot of work to keep it that invisible. I guess stuff like inventory management is similar: a lot of effort and a thankless task for something that works, but don't put in the effort and the complaints will come as a torrent.
