That surely is not the first time a helmet hasnt come back in the next installmentthough other thing is that a helmet has returned or rather its name has since sometimes the design has changed so drastically that it basically looks like a different helmet.
As for the timmy helmet, it doesnt look that bad when compared to many other helmets in these new helmets meaning H4 forwards, so i dont see as to why it wouldnt return given it also seems to be somekind of 343i thing now.
But overall the armor pool, helmets included obviously, needs to be drastically shrinked like getting rid of many of the helmet designs. For example, we basically have multiple different EVA variants in H5g.
Quality over quantity, less amount of armor sets but more customization points. Much like in Halo Reach where armors were recognizeable even if they were lesser in numbers but numbers dont mean anything if there are over 200 armor sets that are hardly distinquishable from each other and half of them being reskins.
Speaking of reskins, those shoild have their own category/ sub category to make the menu clearer so i dont have to scroll through hundreds of reskins to find basically anything even little different.