For me the headsculpts are the main selling point of these figures, alongside the soft goods materials. But most of my favourite characters wear masks. I'd never display my one Vader unmasked, Shaw or Hayden head, you know? Or have any Spider-Man or Iron Man without their masks on (it's why I'm still praying for HT to release a Tuxedo Tony). I will buy the inevitable ROTS re-issue in 2025, so I'll have a proper Obi-Wan too. Like you said, I see this get-up as the very definition of a Jedi Knight, at least in the PT Era, so the helmet does put on an extra flair. It adds to the Knight/Hoplite imagery. It's just that you lose the aspect of it being clearly Obi-Wan and it becomes more "faceless". But it is more unique as a look. Decisions, decisions...
I'm a "museum poser" more or less in general, but I do have this urge to create a sort of "battle diorama". You know how in the 90s X-Men opening you've got the X-Men and Brotherhood running towards each other? Similar thing, with Obi and his Clones on one side, and the PT Villains/Sith on the other. Not on running positions, just being seen from the side, all of them in action poses instead of museum/"cool and static" ones. I do however think that such a display would "obscure" them a bit, as they wouldn't be seen from the front. Maybe I could go with a forced perspective, type of thing? I suppose I'll have time to dwell on that. First they'll have to make a Ventress and a Grievous, then I'll have to hunt down, or wait for reissues for, Dooku and Maul, and so on. I figure the CW Anniversary might give me some of the Clones I want this year, so there's that.