You can't say Aasimar without Aasssss... and there's your problem right there. The name is problematic. Also the hook is not strong. Aasimar look like... pretty people with silver hair? D&D lore already has a plethora of races that are basically "Human, but a different color." And how do you roleplay one? Is it just a goody-two-shoes human? There are plenty of those as it is.
I think the Deva was intended to be a reimagining of the Aasimar. I'll admit it was a pretty radical one. But I do think that the Deva concept was quite successful. I had several players that wanted to play one (and I did too) which I can't say for any of the other new races introduced in 4e. Deva have a distinctive and interesting appearance and a strong roleplaying hook.
Whether or not they take another crack at re-working the Aasimar, I hope to see the Deva reincarnate for 5e.
Not all Aasimar looked the same. Yes some, specifically those descended from Solars looked metallicy in skin and hair, but one born from a Planatar would more likely have an Aasimar with green skin like an Orion in look.
And in FR things got diverse. An Aasimar of Sharess would be more likely to have skin with cat patterns and other feline traits be more likely to turn to evil then other Aasimar. So FR pre 4e Aasimar was the best Aasimar because they weren't just aligned with them not just with celestials, but with Gods as well.
And let me remind people the 2e/3e Tiefling along with the other planetouched will be in the Planetouched race, whichrace, which is why they didn't include it in the PHB Tiefling. I imagine the Planetouched will be in the MM or DMG I'm guessing.