If you like the way Intensifying Mod handled clothing, I would recommend just using that mod's item_helm/armor/gloves/pants/shoes.txt files. Nothing has changed in those files from .18 -> .25, so it's safe to just copy them over. These files remove most excess clothing types, and turn all remaining clothing into 'armor', which takes no wear damage and can only be worn voluntarily via the military interface, and also causes migrants to show up with no clothing and disallows any clothing claiming.
The only other thing you need to edit to complete this is entity_default.txt, which contains references to each individual clothing item for each civilization. Again, you can copy the blocks of armor allowances from Intensifying's entity_default.txt, and paste them over the ones from .25 (don't copy the whole file, as there are new things in this file in .25). For example, under [ENTITY:MOUNTAIN], replace all of the lines starting with [ARMOR down to the line before [SHIELD, i.e.: [ARMOR:ITEM_ARMOR_BREASTPLATE:COMMON]
[ARMOR:ITEM_ARMOR_MAIL_SHIRT:COMMON]
[ARMOR:ITEM_ARMOR_LEATHER:COMMON]
[ARMOR:ITEM_ARMOR_COAT:COMMON]
[ARMOR:ITEM_ARMOR_SHIRT:COMMON]
[ARMOR:ITEM_ARMOR_CLOAK:COMMON]
[ARMOR:ITEM_ARMOR_TUNIC:COMMON]
[ARMOR:ITEM_ARMOR_TOGA:UNCOMMON]
[ARMOR:ITEM_ARMOR_VEST:COMMON]
[ARMOR:ITEM_ARMOR_DRESS:COMMON]
[ARMOR:ITEM_ARMOR_ROBE:COMMON]
[HELM:ITEM_HELM_HELM:COMMON]
[HELM:ITEM_HELM_CAP:COMMON]
[HELM:ITEM_HELM_HOOD:COMMON]
[GLOVES:ITEM_GLOVES_GAUNTLETS:COMMON]
[GLOVES:ITEM_GLOVES_GLOVES:COMMON]
[GLOVES:ITEM_GLOVES_MITTENS:COMMON]
[SHOES:ITEM_SHOES_SHOES:COMMON]
[SHOES:ITEM_SHOES_BOOTS:COMMON]
[SHOES:ITEM_SHOES_BOOTS_LOW:COMMON]
[SHOES:ITEM_SHOES_SOCKS:COMMON]
[PANTS:ITEM_PANTS_PANTS:COMMON]
[PANTS:ITEM_PANTS_GREAVES:COMMON]
[PANTS:ITEM_PANTS_LEGGINGS:COMMON]
..with the corresponding lines from Intensifying's [ENTITY:MOUNTAIN] in entity_default.txt: [ARMOR:ITEM_ARMOR_BREASTPLATE:FORCED]
[ARMOR:ITEM_ARMOR_MAIL_SHIRT:FORCED]
[ARMOR:ITEM_ARMOR_LEATHER:FORCED]
[ARMOR:ITEM_ARMOR_CLOAK:FORCED]
[HELM:ITEM_HELM_HELM:FORCED]
[HELM:ITEM_HELM_CAP:FORCED]
[HELM:ITEM_HELM_HOOD:FORCED]
[GLOVES:ITEM_GLOVES_GAUNTLETS_D:FORCED]
[GLOVES:ITEM_GLOVES_MITTENS:FORCED]
[SHOES:ITEM_SHOES_BOOTS_D:FORCED]
[SHOES:ITEM_SHOES_SOCKS:FORCED]
[PANTS:ITEM_PANTS_PANTS:FORCED]
[PANTS:ITEM_PANTS_GREAVES_D:FORCED]
..repeating this for each of the 5 civ types. This still allows you to make clothing and leather armor for voluntary wear under actual armor, and goblins should only come wearing basic armors and the occasional leather hood etc. You can also remove the hood/cap/pants/etc references from the goblin civ if you don't want them to wear any clothing at all under their armor, just make sure they have some actual 'hard' metal armortypes available like greaves, breastplates, etc.
Edit: If you want to embark in cold biomes, you'll also want to edit tissue_template_default.txt and increase the [INSULATION:100] value for [TISSUE_TEMPLATE:FAT_TEMPLATE] to around 400-500 so that dwarves are naturally more cold-resistant without clothing.