I know Reach bought a lot of customization, but sadly is not enough in my opinion. I wish that all helmets could have all attachments and there would be more customization involved like Armor Detail, Clan Tags(on the actual armor), more Emblems, and the ability to customize your Belt, Feet, Knuckles, and add more detail to the armor such as stripes, battle scars and etc. Foremost i want more Armor for the Elites( if there are any in Halo 4) and that you can customize them the same way you can customize a Spartan.
I love the customisation options in Reach, so I hope they continue that in Halo 4 with even more customisation.
Here is a link to the Official Feedback Thread you can post there if you like to be sure it is seen.
Official Feedback Thread Link
I like the halo reach armor customization options but i do agree that they need to add a little more. Like more armor effects.