Reskinning is great. I do it all the time.
Some Hexblade Blade Locks I've played/ tinkered with:
- A Drow 'Sword Dancer' of Elistraee. Patron refluffed to Elistraee, weapon re-fluffed to Moonsword. The curse is reflavored to 'Blade focus.'
- A Gold Elf Hexblade [Moonblade scion] - his patron and pact weapon is his own families Moonblade which grows in power as he does (gaining thirsting blade, improved pact weapon, eldritch smite etc). The 6th level Spectre abilitiy is simply re-fluffed as the Elfshadow ability common to Moonblades.
- A Gith 'Antipaladin'. Patron refluffed to the Lich Queen, and weapon re-fluffed to a Silver Sword.
Ive also seen Draconic sorcerers re-fluffed to Fiend bloodlines (take red dragon, and the scales, wings etc are all your demonic heritage shining through).
Refluffing is awesome. I'd always allow it as DM - it helps players get concepts on the board. There are zero issues with changing fuff as long as the mechanics stay the same.
Heck, I'll even allow slight mechanics changes. The 'Infernal' draconic Sorcerer gains Infernal as a language instead of Draconic at 1st level; Monks use a 'Monk weapon' with the same stats as a spear or quarterstaff, but called whatever they want (lajatang, dragon sword, nine ringed broadsword, jian, three sectioned staff or whatever) and doing their choice of S, B or P damage, a PC can have a 'Sabre' (same stats as a rapier, but dealing Slashing damage), your Samurai can have a Katana with the same stats as a Greatsword etc.
Id be relutant to play in a campaign where the DM said 'no' to the above. There simply is no good reason for saying no.